ExtremeSpeed / ThunderPunch can replace Pursuit

Ice Punch will destroy Lugia, Latias and Rayquaza. It fails to destroy Giratina only 3HKOing it. It can however OHKO Dialga with Superpower. Those Pesty Steel types won't like Fire Punch all to much either. The last move is really up to you. If you want a priority move that can catch other Deoxys off guard then ExtremeSpeed is for you. Thunderpunch gives you a move that will do some to Kyogre and Ho-oh. Pursuit is for those brave enough to risk it and see if Mewtwo will flee in fear of Shadowball.

(Info taken from J.Kudo)