I've realized I haven't put in any input on my opinion for these sets either, so i'll toss them in now, though most of what I'll be saying has already been said. I can't comment much on DC sets, since I've got no knowledge on popularity of DC characters, but here are my 2 cents for Marvel.
I like the Captain America / Red Skull / Hydra boxes for sure. This might very well be the next wolverine chopper showdown, since all 3 minifigs are made well, iconic, and 2/3 of them are exclusive.
The Electro set is a joke. Spiderman is already in half the LEGO sets, and the Electro looks lazily done.
The new Hulk set with all of the exclusive minifigs is the powerhouse, and i'm predicting it'll be VERY easy to make MSRP through parting out the minifigs alone. Definitely picking up a few of these and including one for myself.
I'm having very mixed feelings about the Spiderman Green Goblin set. This iteration of the GG is hideous, and another spiderman to have to sell off sounds like a PITA. On the other hand, Mary Jane and Power Man (LUKE CAGE) could be VERY exclusive. I just wish that LEGO stayed consistent with keeping the original comic costumes.