You definitely want to play Horde. The best race for a Warrior would be an Orc, but if you can't stand the ugliness of them, I'd say go with Tauren. The three main types of classes for gameplay are tanks (the thing that gets attacked, which would usually be Warriors,) DPS (damage per second, Mages, Hunters, etc.) and healers (Priests and Druids.) Druids can do a little bit of everything.
On the subject of professions, you only get to choose two. Mining makes you a BUNCH of money, Enchanting is rather advanced and expensive, so should be saved for later characters, Skinning & Leatherworking allow you to make armor, but it isn't Mail or Plate armor, which are the highest classes of armor, so it isn't exactly helpful once you hit a high enough level, or if you play as someone that gets Mail or Plate at the start, like a warrior would. If you do go Warrior, I suggest you do Mining and Blacksmithing. I don't remember what Blacksmithing allows you to, because I don't think I ever did it, but I think it lets you make Plate armor...or something. Go find out for yourself.
I prefer a solo game, and if you are doing that, Hunter is the best in my opinion. People don't tend to like them because they are underpowered, but going with a pet (a little helper that hunters get to have [you can go pick up any beast in the game, and you can change it if you want to]) just tends to make everything more enjoyable. If you do go Hunter, I would suggest Skinning and Leatherworking as your professions. They don't get Mail armor until level 40, and never get Plate armor, so Leather will last you a while.
On the subject of what to, it depends on what you want. I seriously think the best thing about WoW is how beautiful the landscapes are. I suggest that the first thing you do is get a Mage (they teleport people) to teleport you to the Outlands, which you will need the Burning Crusades for. You won't be able to kill anything, but just run away from shit and enjoy the landscapes. My best memories are of the Outlands at level 40. People don't appreciate adventure in RPGs as much as they should.