Great thread, full of insights and interest. Thanks.
It's encouraging to hear from this and other sources that one of my biggest fears about 4E may not be a problem. I have been concerned that the characters would feel too similar to each other. Is every wizard just a choice of fire or ice? But the answer seems to be, "No, there are more options that genuinely feel different". That's good to hear.
I also liked the description of characters in Keith's game. A warlock archaeologist with streetwise? Sounds fun. I want people to be able to play interesting characters with unique flavor without totally sucking in combat.
What I'm really looking for is a system so robust that the Bard 11/ Ranger 4 in our current party can make a new character (she wants a wizard next time), that will be fun for her both in and out of combat. Right now in our 15th level 3.5 game, she dislikes combat entirely, and claims that she always has. I doubt that last part only because I remember her seeming to have fun feathering the bad guys at lower levels, but now she uses her bow mainly to propel magic arrows that cause spell effects. She really wanted to raise her non-combat skills such as Diplomacy and her bard spells, so started leveling exclusively in bard.
A good part of the issue is broken 3.5 rules - we're past the place where the math works. What we're seeing is the point where iterative attacks and recalculating attack bonuses due to buffs, debuffs, stat damage, etc make combat painfully slow to resolve. But whatever system we go with, our campaign will always need to include a good mix of combat and non-combat encounters. Intrigue and roleplaying are very important to some of our players, while kicking butt is important to others.
Here's hoping that 4E is fun, and that the preview adventure in May isn't focused on combat to the exclusion of the non-combat skill systems. If there's no chance for roleplaying in that module, I'll either have to make something up myself and insert it, or else worry that the players will denounce 4E as "not RP friendly".