That’s a *great *fit for WoW. One of the recent additions to the game is the Random Dungeon Finder (RDF) tool. Starting at level 15 (which you reach pretty quickly), you can use the RDF to queue either for specific five-man dungeons based on your level, or for a completely random dungeon (which will also be level-appropriate). Based on what role(s) you’ve selected (tanking, healing, or damage), you’ll be randomly assigned to a group of four other people from your Battlegroup (a collection of realms)–or, if you queue with a group, the RDF will fill any missing slots.
Tanks are currently the bottleneck in five-man content, so you’ll always get the fastest possible queues. My main is a tank, and when I queue for my daily Heroic dungeon, five seconds is a *long *wait. You’ll probably be waiting a bit longer at lower levels, but I can’t imagine it would take more than a few minutes unless you’re on at a really odd hour (and even then…).
If you want to tank, your class options are Warrior (Protection spec), Paladin (Protection spec), Druid (Feral spec), or Death Knight (currently all three specs have viable tanking talents, but come Cataclysm (the new expansion), Blood will be the dedicated tanking tree).
**DKs **aren’t available until you have at least one level 55+ character, as well as the *Wrath of the Lich King *expansion. **Warriors **are a great class and the classic tanks of the game–we have a huge toolbox, which IMO makes us some of the best tanks but also means it’s one of the hardest classes to tank *well *with, currently (e.g., you have to work harder to hold AOE aggro than a Paladin). I’ve never gotten a **Pally **past the low teens, but a lot of people enjoy them. They seem to be especially useful for soloing–Plate armor, healing spells, etc. make for great survivability. They’re also arguably the strongest tanking class in the game right now, because of the ease of their AOE threat generation and talents like Ardent Defender. **Druids **are great if you want to try a bit of everything–they’re the only four-way hybrids in the game, because depending on spec and gear, you can play them as tanks (Feral), healers (Restoration), ranged DPS (Balance), or melee DPS (also Feral, but with different talent choices). Feral DPS and Feral tanking also have more gear overlap than any other tanking class.
The one big problem with tanks in WoW is our group role scaling. A five-man requires one tank. A ten-man raid uses two for most encounters, and sometimes just one. But a 25-man raid almost exclusively requires between one and three tanks, depending on the encounter. (In fact, I can’t think of a single regular-mode fight in WotLK that requires more than three.) However, it’s worth noting that going forward into Cataclysm, 10-man raids will provide exactly the same rewards as 25s, so we may see an even greater proliferation of strict 10-man raiding guilds. (There’s also no way to tell how role scaling will work with the new raids until the fights have been seen.)
ETA: Currently, every WotLK raid is available in both 10- and 25-man versions. The 25-man versions are tuned higher and drop better gear.