I've been having a good run with Lum Berry Jirachi:
Jirachi@Lum Berry
Trait: Serene Grace
EVs: 4HP/252Atk/252Spd
Jolly Nature
Body Slam
Iron Head
Drain Punch
Ice Punch
If Drain Punch or Ice Punch aren't going to 2HKO, go for parahax.
Probably shouldn't have posted this here, suddenly...