Yes, BG and BGII are the best single palyer RPGs ever written, but they absolutely suck when it comes to multi-player.
My recommendation is Neverwinter Nights. The single player official campaign is just okay, but the FREE online play can't be beat. The fan base is huge and some of the fan built mods are even better then the BioWare built stuff. BUT... the pinicle of the whole shooting match is DMed games. Other than Vampire the Masquerade, there has been no other game that allows for a Dungeon Master to control things from behind the scenes. It's like no other gaming experince I have ever had. Once you get hooked you will never want to play another RPG again.
Official Neverwinter Nights Site:
http://nwn.bioware.com/
In order to make the Neverwinter live up to all this, you really need to be a member at Neverwinter Connections. It gives the players the ability to schedule games so that you can run a whole module with the same players/characters. Here is the game page for my current campaign...
http://www.neverwinterconnections.co...e/id/15391.htm. I figure this campaign will take over 150 hours in weekly session to complete, and will take the characters from 1st level to +20th level.
Also, check out the NWCon 2.5 page:
http://www.neverwinterconnections.co...on/showcon.htm. This is the twice yearly online convention hosted at NWConnections. All the games must be either "open" or "application" and they regularly host IRC Seminars and In-Game Seminars.
As far as content, there is more stuff at the Neverwinter Vault then you could ever play in a life time. Go to the module index and you will see what I'm talking about
:
http://nwvault.ign.com/Files/modules/moduleslist2.shtml. I can't even guess as to how many module are posted to the vault. Needless to say, you will NEVER run out of stuff to play.
Finally... all this is FREE once you buy the game. In all honesty, I haven't even thought about buying a game since I got into NWN. Now, granted, I'm an old school D&D player from my early childhood, so I'm a bit partial to the ruleset and setting. I just can't see the attraction of Pay to Play.
Check it out, you might just find what you are looking for.