|Just when you thought the Nerfbat got them...|
Blood Angels: Yes the FNP "nerf" hurts a bit, but everything else got better, especially as they can ally in some cheap long-range support to help their jumpers out. They have the best variant of Stormraven for aerial combat and FNP Terminators of any kind are just unstoppable without lots and lots of S8 AP2.
Necrons: Gauss is no-kidding now.... learn to fear the sixes. Ghost Arks are crazy tough and CCBs get all the new chariot rules. Also, pimped out Overlords fear absolutely nothing any more. Night-fighting is also quite a bit more hardcore now, so pulses help a lot. I know I plan on building these guys ASAP, as I think they are now possibly the codex to beat. The only thing that could hurt them is the lack of ally shenanigans.
Dark Eldar: Free 5+ invulnerable for all their skimmers (as long as they get to move) and the ability to ignore all night-fighting. Also, Ebony/Ivory Eldar tag-teams could be quite hilarious. I don't think anything wants to get doomed and then zapped by splinter weapons.
Shoota Orks, Blob Guard, and Devilgaunts: Overwatch will destroy any unit trying to charge cheap, shooty, fodder units. You have been warned.
Back to my original post title... I think my two main armies of Space Marines and GKs survived the transition to 6th very, very well. My Smurfs are loving the love to LRs, Lascannons, and Termies (not to mention beatstick characters like Papa Smuf). My Honorguard GKs took a few hits, namely in the loss of power weapons and in the ability to transport Pallies in a Stormraven (It is a deathtrap now), but it wasn't as bad as I feared. The Teleporter DK should hopefully be a flying MC which gets it some nice buffs, and if I am reading the rules correctly it is automatically S10 with Nemesis Doomfists... and is a Character for challenges to boot.
What made me the happiest though is that Pallies are ALL Characters. That means that the new wound allocations rules didn't completely destroy them like everyone hoped. They all get "Look Out, Sir!". Ideally, Draigo will be in front and absorb most S8/AP2 shots, but the Pallies can absorb small arms fire for him on a 2+. If they do get out manuevered and a non-Draigo model gets targetted, then Draigo or other Pallies can also suck firepower from that model. Yes, it is only on a 4+, but that still allows them to shunt wounds around and still retain a measure of survivability. The only thing that scares me is Terminators (Meganobs especially), as I can no-longer count on my NFWs to chew them up. I am going to try and get a game in tomorrow, but I expect that my squad of Draigo and five Pallies is going to get to stay in my army list. That alone makes me a happy camper.