So, the Alt Project. Long-time readers of this blog may remember this idea. I get one of each class to 30 and then talk about it. 30 was chosen because it was mount level at the time. Well, since then mount level's been lowered to 20, and all of the alts are at least 20, so I'm calling it done. So here's my final conclusions...
Druid-> I have my ups and downs with the druid. The first 20 levels are not fun, but once you get kitty form things pick up. I hit 60 and respeced to moonkin, which I enjoy in dungeons but not so much running around the world. I'm currently contemplating respecing back to feral, but I'm keeping my broccoli second spec. Healing is different from any other class, but quite fun. This is a great class for trying all the different roles available to you in WoW, and I would heartily suggest rolling one if you haven't already. LFG queues can be quite short if one of your specs is tree or feral tank, and you should be able to heal in moonkin spec well into Outlands. Not so sure on tanking in feral dps spec, but I'd guess you can get away with it until 40 or 50 with decent gear. As far as soloing group quests, I would guess you can, but I have yet to try it.
Hunter-> YAY! Slow to start but once you get a pet it's so fun. However the first 10 levels are a bit slow, so you might want to wait until Cat to roll a hunter alt. Also, hunters are dps, and only dps, so lfg dungeon leveling can be slow. They completely make up for that with incredible solobility. This is one of those classes that can solo many group quests.
Mage-> Many people in my guild say you have to be a special kind of crazy to love mages. I agree. I lack that crazy. Painfully slow, but explosions are fun. It's also good practice for when your pet can't hold aggro worth a damn and you have to play the burn them down before they hit you game. As far as lfg goes, playing a mage in a dungeon is nothing like soloing with one, and is great fun. AOEfest for the win. You still go squish easily though, so keep an eye on that threat meter or trade water for extra heals.
Pallies->Make it past the first 20 and they're great. But the first 20 are kinda painful/boring. Okay, mostly boring. Then you become INVINCIBLE. Not really, but a plate-wearing class with self-heals, buffs, and some nice damage abilities is nothing to sneeze at. Prot pallies are also generally considered the kings of AOE tanking, and pally tanking is quite easy to pick up and learn. A great class for LFG, as tanking and healing still get quick queues. This is another of those can solo many group quests classes.
Priest-> Ranged dps while insanely squishy. Not my favorite thing. I want a pet. Same problem as mage, really, just mitigated by self healing. But once you get into the higher levels, it gets much much better. Another good class for LFG, and you can heal in shadow spec until Outlands at least. Remember your wand and stacks of drinks are your friend in those low levels, and you'll be fine.
Rogue->Not wowed by the other mechanics, but sneaking rocks. Again, as only dps you'll have LFG queue issues, and with the squishiness, I'd wait till Cat when they get a self-heal. On the other hand, no class rules PVP quite as completely as rogues do, so if PVP is your thing I would certainly recommend trying it. If you're curious about how rogues play, but don't want a toon limited to melee dps, roll a druid and go feral kitty. It's not the same, but gameplay is similar.
Shamans->Not quite as awesome as pallies, but still quite fun. Plus you can do either melee or ranged dps. You can heal as elemental till 60, and once you get the totem bars things simplify dramatically. Just remember to put totems down, and heal self as needed and you should be good. Not many LFG issues, since you can queue as heals or dps.
Warlock->Doom and pets! More DoTs! This is probably the closest to the hunter class, so no wonder I find it fun. Again, the dps lfg problem rears its ugly head, but this is a very soloable class, so just go quest while you wait for that queue to pop. Do watch aggro in dungeons, remember no excessive life tapping, and switch out your voidy for another pet when lfging.
Warriors-> This class is the quintessential tank class, and most people in lfg will expect you to tank. This is not my favorite class by a long shot, but it does have its moments. Just make sure you have some health potions on hand, especially for those first levels. Stance-dancing is also an option, and can be quite useful. To anyone wanting to hit stuff with a weapon, the warrior's a great class. I just don't really like hitting stuff with weapons.
Final Thoughts: I'm not a melee dps fan, so warrior and rogue aren't really my favorite classes. Mage is a bit squishy, but seriously go run a 5man before you give up on the class. Trust me, it's completely different and a lot of fun. Shamans and pallies are a bit bewildering at first, with all the buffs and hammers and auras and totems, but once you get those figured out they're fun. Warlocks and hunters are always great, and probably the classes I would suggest to brand new players who want to dps at range. Melee dps would be rogue or warrior, since pallies are a bit boring for those first 20 levels. I'd suggest a pally or druid for someone who wanted to tank (nothing against the warrior, but both pallies and druids are a bit more flexible role-wise), and for a healer I'd suggest druid or shaman. Given the pally's lack of group healing, something I find rather frustrating, I wouldn't suggest them, and priests, well, slow-leveling combined with squishiness means I would save them until 3rd or 4th alt.
As far as where my alts are, the rogue is being ignored, the warrior's now a cloth bank alt, the mage is hanging out at 30 till further notice, the shaman's being leveled slowly as is the pally, and the DK and druid are in a holding pattern till the shaman and pally are done, or until I respec the druid and try feral again to see if it's more fun.