I would have posted sooner, but I cannot access GB while at work
Anyway, I've also been playing Warcraft and it has become my main game. I have played other massive online RPG's (Everquest 1 & 2, Dark Age of Camelot, Anarchy Online, Star Wars Galaxies) and this is definitely one of the more soloable ones.
Ray, I'm on the Perenolde server, which was added after the original servers became overloaded. I assume you are on one of those older ones since you started before I did. My undead warlock (another one!) is level 28. I'm also in a guild but the game gives you so much to do on your own, I haven't had to group much.
Ingie, and anyone thinking of trying an MMORPG, the main difference from single player, offline games is the fact that you cannot save your game, it is a perpetual world, meaning it goes on even when you are not playing. It does not save game data that you can re-load later, so if your character dies you are subject to the game's death rules.
World of Warcraft has a very forgiving death system: if your character dies in a fight, your "ghost" spawns in a nearby area and you have a choice of either going back to where you died and clicking on your corpse to resurrect, or resurrecting right then and there with a temporary penalty to your stats.
Another difference is the cost. The inital cost is $50 and then $15 a month after the first free month. Some MMORPG companies make expansion packs which add a significant amount of content to the game, but you usually have to shell out more money for that too. My feeling is, if you enjoy the game and want to explore it's vast amount of gameplay, most likely you won't spend money on other games, so it's debateable whether you are spending more on a monthly basis playing one MMORPG vs. playing 2 or 3 single player games in a month.
I generally don't like to group with other people, which is why I left Everquest 2, a game that practically forces you to group with others due to the way that game was designed. Warcraft pulls off the trick of allowing solo or group play depending on what you want. If you want to solo, there are numerous quests to do, or you could just explore the different zones killing enemies. There is also a fair amount of group-oriented content, such as elite quests and dungeons. Six people is the max for a group, I believe.
Regardless of whether you are grouped with others or not, you can communicate with other players in your zone through the chat window. One of the reasons I love playing these big online games is the immersive feeling of being in a huge, perpetual world knowing other people are playing at the same time I am.
HOWEVER, after all that, I should point out that Blizzard, the makers of Warcraft, have suspended shipment on any new copies of the game until they make some technical adjustments to the game servers, so if you are thinking of rushing out to buy it, you probably won't find any copies at the moment, at least according to this article: FILEFRONT