I love WoW. Then again, I have a group of friends to play it with, who I all know in real life, and we all do things in the game together and congratulate each other on our achievements and stuff. So, I imagine the game is probably made a lot more fun for me.
The race and class you choose all depends on your personal playing style. However, the game lets you experiment with the different races and classes all you want! There's no character limit to my knowledge except the one of 20 characters per server, and the fact that on PvP servers you can only have characters on one side (either Horde or Alliance.) Both sides are pretty much equally fun IMO, the only difference being some of the locations in which you level and a few instances you can run, therefore giving you different quests and sometimes different loot.
WoW is fun pretty much all the way through. There's always something to keep you busy. Sick of questing? Go run some instances (a new one is available to you almost every 5 levels!) and get some gear for your character. Sick of that? Go PvP! Still sick of that? Go screw around the massive world with some friends and look for secrets, or just explore.
However, WoW does have some negatives:
- Endgame, especially for my class (Paladin) has some problems. Pretty much, if your class can heal, you end up healing in the endgame, even if you can do other things equally well. That's just the way strategy works.
- It can get very repetitive at times. I stopped playing WoW for a month around level 40 to give myself a break. The quests aren't that original, it's mostly get this drop or kill this amount of enemies; it's instances with 5-man groups that break up the monotony of PvE play. These require strategy, teamwork, and planning, and they're great fun.
- It can be a little slow to get into until you break out of the little noobie area.
However, WoW is very accessible and the community is generally great, at least on my server. However I recommend you have some friends to play through it with.
