It's completely conjecture, since no one really knows what Inferno is like, or even what the skill system is going to look like for final release. Judging by today's iteration of the skill system, I'd have to say Wizard would get my vote. Strong AoE and good utility skills are littered at just about every level of each skill section. Not getting hit is still the best defense, and a stand off caster has that going for it. Additionally, cold, fire, or arcane damage types are all just a simple skill change away, for dealing with resistant packs.
After that, I'd say Witch Doctor. Pets that can tank always add security, and there appears to be enough AoE and control to deal with threats. I'm biased by how safe I always felt behind my Necro skeleton shields in D2, but I suspect this will be a good hardcore class as well.
I wanna say DH is my third choice, and I guess it is. I just didn't love the class. It seemed a bit of a one trick pony to me, damage on top of damage. There's only a tiny handful of utility, cover your butt type abilities. Caltrops is pretty amazing though, that skill alone is probably the primary reason I place DH in the top 3.
Monk and Barb I rate as about equal, with a nod to the Monk for added versatility. I don't choose melee if i want safety, since melee exposes itself to the greatest risk. I'm sure well geared members of both these classes will find their way through. Anyway, that's how I see it. We'll have to see how things shake out in the coming weeks and months.
Edited by D3BETA on 2/12/2012 12:12 AM PST