Crap.
Period.
Blizz did something interesting with WotLK; all of a sudden there's still a ton of new quests to do after u hit 80. Most people will lvl somewhere in Storm Peaks at worst which still leaves all or most of Icecrown to contend with. BEfore in TBC when u hit 70 that was pretty much it leaving only dailies on that godforsaken place called Queldanas and raids to keep you busy.
... ofc you could always jsut level a new toon. Which is why I ended up with 4 lvl 70's.
So now you can still quest after u hit 80. There are more factions to contend with as well so have fun getting those dailies out the way.
Raiding is still pretty special but there are more people doing naxx, os, and voa but not too many successfully in ulduar. In that place one player can't save ur butt - everyone has to be on top form or you're squished.
IMO the long term players (I'm 2yrs+ on wow) will always see something different and new to aim for. Whether you still have a pvp spec, a twink, an AH God, a pve raider extraordinaire there's always something to do.
Its like they say in that advert: Where do you want to go today?
FYI I now have 3 lvl 80's, lvl 71, lvl 14, and a lvl 7. WoW keeps getting better especially with the new crop of Wowers that have jsut joined our guild. Gotta love this game!