It's probably got to be groudon, right? Kyogre can crush him with its specs set almost no matter what, either ice beaming slower ones or surfing faster ones. Considering specs is a really standard set, it's not really a stretch either. I believe calcs earlier in the thread confirm this.
CB ho-oh might defeat manaphy, but then again, bulky sets aren't entirely uncommon on manaphy, especially physical defense on CM sets, and there's probably a viable spread that tanks a hit and counter-Ko's. And it can also outspeed ho-oh if it's ev'd to do so. Maybe manaphy/ho-oh is one to watch, though.
Giratina and giratina-O is just a ***ing mess, because they're both so brutally similar. I'd have to ask, though-is there a spread commonly used that can take any hit from a giratina, draco meteor it, and then shadow sneak it for the KO?
And sashrai beats mewtwo pretty well, except for Lumtwo.
Man, forget what i said-this is an open race. So this should be fun, although i think groudon's the worst off right now. (Really fast yache berry set??)
Oh yeah, and let's not even touch zekrom/reshiram-zekrom has the slight advantage because it can't miss, but that just makes it 45/55, still almost a coin toss.