Wrath Of The Lich King is just an expansion pack, it's not a whole new game. Now if your asking for my favorite expansion pack then it would be The Burning Crusade.
I'm not sure I understood the question, but I agree with LazyOne. Vanilla was the most fun it ever was for me, finding out new stuff everyday. Unlike the grindfest it is now =/
If you mean expansions... im not really a vet enough to have played vanilla but I thought WotLK was pretty pointless... and to sniper you don't have to get too into it to be succesful you just need to know how to play. I played maybe 10 hours a week for 2 years and had 3 level capped characters (4 if you include my death knight but I dont really) I wouldn't base my playing experience on how much money I put into it because $15 a month isn't really that bad if you find it enjoyable enough to play it semi frequently because it doesn't end where as a game I own after $60 im done with after maybe 20 hours ($3/hour) where WoW I could keep coming back (I quit recently because after 2 years I needed a break... atleast till cataclysm maybe) where as WoW my rough play time was around 1040 hours for about $450 ($2.30/hour) so in actuality I got more bang for my buck with WoW than I did with almost any console game
