I used to play text MUDs, but I haven't for a long time.

I don't bother with competitive multiplayer anymore, so my favorite online game is probably Everquest 2. It's pretty much been ruined now by the idiot development team (though I still think it's better than the competition), but looking back a few years, it provided a great balance between detail and approachability. Its expansive feature set, detailed game mechanics and heavily textured presentation made it a much more complete and interesting game than your stock WoW-alike, in my opinion. However, it was still pure power fantasy, not a spreadsheet, and so I didn't have to work too hard to have fun with it.

My main problem with online games is that I have no one to play with, but I get bored quickly playing alone.

There are definetly some whiny loser kids in GW, but the way the game is made, you don't really have to deal with them.

As for cheaters, there's been a few exploits in GW's history, but cheaters always end up getting banned. If it was a PvE related cheat, their effect on the game was usually small (screwing up the economy a bit, but GW's economy is a joke anyway). PvP related cheats never last long, Anet's always been pretty serious about those (unless it's sync-entry in random arenas, but that's pretty minor).

Oh yes, in my younger days I played on the Valheru MUD a LOT.

Wouldn't know. I play it strictly single player on the Japan/Asia servers which are deserted.

Online gaming wise, and outside of co-op versions of shooters, I've tried:
- MUDs/MU*s (I've played both hack and slash/pvp ones as well as roleplay ones, and a mix of in between)
- MMOs (LotRO, DDO, Warhammer, a bit of WoW, a bit of AoC, CoH, some other F2P ones, and a few other game demos and betas)
- Browser based games: Neopets, Utopia, KoL, Abyss-UK are the main ones I remember that I've played for more than a couple months in the past. I've played a number of other ones but my interest never really lasted long in them.

There are a whole lot of crappy ones that are based upon the same kind of tired premises (a shallow kind of resource collecting or xp gaining via limited number of turns each day). KoL transcended that because it was funny, but also because there were many things to do outside of your turns per day (ie, shopping, chatting, etc). Other tired premises (to me) include the usual war themed ones where it's all about micromanaging your troop/building build order by logging on immediately after the building was done so you could queue up the next one etc, and having some mix of offensive and defensive troops in your army. Not bad but at this point nothing unique and exciting. I don't know the name of the codebases, but I've seen a couple of games which were essentially identical to each other, just the background story/names of places you visit and the currency etc was different, but the underlying codebases were exactly the same as each other, just reskinned, and that would fail right away for me too.

For me, I like uniqueness, something creative rather than the "tried and true". I like a system where you could be on as little (to a point) or much as you liked in a day, but doesn't punish you for not being on like clockwork at X:00 every day or something as your building queues dictate. I don't mind a capped number of turns per day if that's the direction of game design, but I guess I'm saying that there shouldn't be (again, to me) nothing at all you can do in the game once your daily turns are done. A good community would help a lot with this but it's a bit of a chicken and egg thing there; but I guess a good part of this is the devs nurturing a good community culture. There are some really crappy ones with lots of flame wars, and on the other hand I've seen a PvP based PBBG where even the opposing sides were very friendly with each other and everyone helped newbies and seemed quite sporting with each other (Movoda - that was the impression I got of it at least when I tried it for a couple weeks). A monitored forum or ingame general chat system would help here too to keep people hooked/occupied.

My favourite online games are:
- MUDs: Medievia, back when I was playing it, for the clan communities and random loot system and lots of ingame random events/immortal-run games. They had some political/licensing issues and a bad name in the mudding community at large but I kept out of reading all those. Achaea wasn't bad too as they had a complex codebase and light RP, but it seemed too immature and pay-to-win overall.
- MMOs: I like LotRO, but every MMO has its valid criticisms and drawbacks.
- PBBG: Not sure. I played Neopets for 2-3 years and was good at restocking, netted enough rares to top a prominent list for over a year so got spammed to hell and back with admirer/beggar mails ugh. The general community there is really bad, though there was a decent base of nice people too. Barely ever really played their flash games, which a lot of newbies that try Neopets get hung up on thinking that that was the focus of the game. I liked Neopets and KoL because I loved the hunt for random loot. I guess that's a common theme with me too. :) I liked the general community in KoL and Abyss-UK a lot, too.