I've played Persistent World for a while and I think the current online population is still high enough for a fun time.
Be sure to check which server though, some players tend to ignore the roleplaying aspect.
I quit Persistent World, because either the map got LOTR focussed or several regular players only-and-only played as 'robbers', who were terrible at RP'ing and exploiting the server rules to the maximum. (ie. they provoke a lot and kill as soon as they see fit, whine as soon as they get killed after provoking)
Basically this mod remembers your current class/gear (servers do restart once in a while though) and you got a real persistent banking system, which uses a MySQL connection (I believe) to store/retrieve gold amounts.
cRPG also stores skills and such, but I never got into cRPG, so someone else could tell you about this.
NordInvasion also stores skills and such to be persistent, but that's a co-op mod.
I'm sure there are more out there, but these are the ones I know.. and are active