http://www.smogon.com/dp/pokemon/dialga
I've been using this set to great success in ubers for some time, so I thought I'd write up a peer edit for it. I apologize if someone already made a Peer Edit for this set.
[SET]
name: Choice Scarf
move 1: Draco Meteor
move 2: Thunder
move 3: Dragon Pulse
move 4: Aura Sphere / Earth Power / Overheat
item: Choice Scarf
nature: Timid
evs: 4 HP / 252 SpA / 252 Spe
[SET COMMENTS]
<p>This set attempts to patch up Dialga's lackluster (in uber terms) speed by giving him a Choice Scarf. Even without the boost Expert Belt or Choice Specs provides, Dialga will still be putting massive dents in the opponents with Draco Meteor. With Stealth Rocks up, Draco Meteor will always 2HKO standard 40 HP Mewtwo with Draco Meteor, and will almost always OHKO 4 HP Darkrai. Standard Latios (4 HP / 0 SpD) is always OHKOed by Draco Meteor, though his more defensive sister Latias will always survive if EVed defensively. Thunder strikes down Kyogre, whereas Dragon Pulse is useful for late-game sweeps. Aura Sphere allows for consistent damage against enemy Dialga (though it's utterly futile against Blissey), whereas Overheat is an easy OHKO on all Scizor, Forretress, and Metagross. Earth Power is an option for Jirachi and Metagross that isn't dependent on the weather, and it hits enemy Dialga for the same base power as Aura Sphere.</p>
<p>The main reason to use this over other popular Scarfers, such as Scarf Palkia and Scarf Kyogre, is the resistance to Normal granted by its Steel-typing, making it the perfect revenge-killer to the deadly Swords Dance Extremespeed Rayquaza. Aside from that, there is the obvious surprise factor, as most Dialga invest very little in speed anyways and certainly aren't expected to be outspeeding Base 150 Speed Pokemon. Dialga's bulky defenses and near-perfect typing allow to take a few hits, which is something most other Scarfers (like Palkia) can't boast.</p>
<p>Although Dialga can go physical with Scarf, it's not recommended because of his lower physical Attack and lower base power moves. Likewise, going mixed is not a good idea because Dialga is forced to invest many EVs in SpA/Spe and won't be 2HKOing Blissey with Brick Break anyways. If tying other Base 90 Speed Choice Scarf Pokemon (Kyogre, Groudon, other Dialga) isn't a concern, 204 Speed EVs allow it to outspeed Deoxys-A, with 52 EVs in HP for more durability.</p>
I've also decided to write up the Special Choice set in case the general consensus is to merge it into one set.
[SET]
name: Special Choice
move 1: Draco Meteor
move 2: Aura Sphere
move 3: Dragon Pulse
move 4: Thunder / Overheat
item: Choice Specs / Choice Scarf
evs: 4 HP / 252 SpA / 252 Spe
nature: Timid / Modest
[SET COMMENTS]
<p>With 150 Base Special Attack and Dragon STAB, Dialga has potential to cause a lot of damage in ubers attacking from the special side. A Choice Specs-boosted Draco Meteor from Dialga is one of the most powerful special attacks in the game, and anything that isn't a Steel-type and isn't Blissey will have a very hard time switching into it. Aura Sphere, Thunder, and Overheat take care of the former with ease, though Blissey will be able to switch in and stall Dialga out with ease. Aura Sphere is a 2HKO against Tyranitar and opposing Dialga if Dialga is holding a Choice Specs, and a OHKO against the omni-present Darkrai regardless (assuming it's at least taken Stealth Rocks damage). Thunder is the more practical choice because it takes advantage of Rain, it OHKOs most Kyogre, Lugia, and Manaphy without the SpD drop, and it has a chance of paralysis. However, if one is using this on a team with Groudon, feel free to run Overheat to OHKO all Steels (barring Dialga and Heatran), as opposed to a 2HKO from Aura Sphere or Thunder.</p>
<p>The choice between holding a Choice Scarf and Choice Specs depends on whether you want the raw power from Choice Specs, or the extra Speed from Choice Scarf. Choice Scarf allows Dialga to revenge-kill Darkrai, Rayquaza, Palkia, Deoxys-A, and Kyogre, among other threats. However, Scarf Dialga lacks the wall-breaking ability of Specs Dialga, who can fire off Draco Meteors and be sure to cause some damage. If you choose to equip Choice Specs, feel free to use an EV spread of 224 HP / 252 SpA / 32 Spe, which outspeeds Adamant Tyranitar, and gives Dialga more opportunities to switch in against the likes of Kyogre, Palkia, and Manaphy.</p>
I've been using this set to great success in ubers for some time, so I thought I'd write up a peer edit for it. I apologize if someone already made a Peer Edit for this set.
[SET]
name: Choice Scarf
move 1: Draco Meteor
move 2: Thunder
move 3: Dragon Pulse
move 4: Aura Sphere / Earth Power / Overheat
item: Choice Scarf
nature: Timid
evs: 4 HP / 252 SpA / 252 Spe
[SET COMMENTS]
<p>This set attempts to patch up Dialga's lackluster (in uber terms) speed by giving him a Choice Scarf. Even without the boost Expert Belt or Choice Specs provides, Dialga will still be putting massive dents in the opponents with Draco Meteor. With Stealth Rocks up, Draco Meteor will always 2HKO standard 40 HP Mewtwo with Draco Meteor, and will almost always OHKO 4 HP Darkrai. Standard Latios (4 HP / 0 SpD) is always OHKOed by Draco Meteor, though his more defensive sister Latias will always survive if EVed defensively. Thunder strikes down Kyogre, whereas Dragon Pulse is useful for late-game sweeps. Aura Sphere allows for consistent damage against enemy Dialga (though it's utterly futile against Blissey), whereas Overheat is an easy OHKO on all Scizor, Forretress, and Metagross. Earth Power is an option for Jirachi and Metagross that isn't dependent on the weather, and it hits enemy Dialga for the same base power as Aura Sphere.</p>
<p>The main reason to use this over other popular Scarfers, such as Scarf Palkia and Scarf Kyogre, is the resistance to Normal granted by its Steel-typing, making it the perfect revenge-killer to the deadly Swords Dance Extremespeed Rayquaza. Aside from that, there is the obvious surprise factor, as most Dialga invest very little in speed anyways and certainly aren't expected to be outspeeding Base 150 Speed Pokemon. Dialga's bulky defenses and near-perfect typing allow to take a few hits, which is something most other Scarfers (like Palkia) can't boast.</p>
<p>Although Dialga can go physical with Scarf, it's not recommended because of his lower physical Attack and lower base power moves. Likewise, going mixed is not a good idea because Dialga is forced to invest many EVs in SpA/Spe and won't be 2HKOing Blissey with Brick Break anyways. If tying other Base 90 Speed Choice Scarf Pokemon (Kyogre, Groudon, other Dialga) isn't a concern, 204 Speed EVs allow it to outspeed Deoxys-A, with 52 EVs in HP for more durability.</p>
I've also decided to write up the Special Choice set in case the general consensus is to merge it into one set.
[SET]
name: Special Choice
move 1: Draco Meteor
move 2: Aura Sphere
move 3: Dragon Pulse
move 4: Thunder / Overheat
item: Choice Specs / Choice Scarf
evs: 4 HP / 252 SpA / 252 Spe
nature: Timid / Modest
[SET COMMENTS]
<p>With 150 Base Special Attack and Dragon STAB, Dialga has potential to cause a lot of damage in ubers attacking from the special side. A Choice Specs-boosted Draco Meteor from Dialga is one of the most powerful special attacks in the game, and anything that isn't a Steel-type and isn't Blissey will have a very hard time switching into it. Aura Sphere, Thunder, and Overheat take care of the former with ease, though Blissey will be able to switch in and stall Dialga out with ease. Aura Sphere is a 2HKO against Tyranitar and opposing Dialga if Dialga is holding a Choice Specs, and a OHKO against the omni-present Darkrai regardless (assuming it's at least taken Stealth Rocks damage). Thunder is the more practical choice because it takes advantage of Rain, it OHKOs most Kyogre, Lugia, and Manaphy without the SpD drop, and it has a chance of paralysis. However, if one is using this on a team with Groudon, feel free to run Overheat to OHKO all Steels (barring Dialga and Heatran), as opposed to a 2HKO from Aura Sphere or Thunder.</p>
<p>The choice between holding a Choice Scarf and Choice Specs depends on whether you want the raw power from Choice Specs, or the extra Speed from Choice Scarf. Choice Scarf allows Dialga to revenge-kill Darkrai, Rayquaza, Palkia, Deoxys-A, and Kyogre, among other threats. However, Scarf Dialga lacks the wall-breaking ability of Specs Dialga, who can fire off Draco Meteors and be sure to cause some damage. If you choose to equip Choice Specs, feel free to use an EV spread of 224 HP / 252 SpA / 32 Spe, which outspeeds Adamant Tyranitar, and gives Dialga more opportunities to switch in against the likes of Kyogre, Palkia, and Manaphy.</p>