Hello,
Wow has all that and some. IMHO WoW is the best game out there and im a MMORPG veteran.
Awesome graphics? Its subjective i suppose. I perosnally like them (and liked DAoC original graphics) although they arent the best graphics in the genre.
Smooth gameplay? Again subjective. I know people that can play under the minimum requirements. For best play you will want lots of RAM and a decent vid card, like all MMORPGs. I have average vid card and only 512 ram but i can get 35+fps (with settings halfway up or higher) easily.
Quests? OMG you will be swamped with people needing your help. There will never be a time when you arent on a quest.
Character customization? Eh..not so much. Limited facial features, but most people customize with gear, pets, weapons, etc. Mostly, you "customize" with role playing and building a reputation.
Free trial? Yep 1 month free. Seems to be the norm when you buy most MMRPGs.
The best features in WoW IMHO are: immersion and setting, quests and questing system, PVP , instance dungeons, graphics (to some degree), sound, game engine and mechanics (little things mean ALOT), and the of course the skullcrushers.
Hope i gave you enough to go on. More specific info can be found http://www.worldofwarcraft.com/. We need good priest btw! >;]