I'm more of an indy gamer--small games gives a small community and a dev team that actually cares and knows about the player's concerns!
So... Top of list: Darkspace (cause I like scifi ship based games...comparable to eve, except you actually get to control your ship's weapons unlike eve's autofighting....I think) Heroes in the Sky--just finished NA closed beta, from a korean version...their events actually don't sound corny! Navyfield--...and of course, I like ship based games ^^ it's a nice game, if you play it: if you go carrier, be sure to have tough skin...you get blamed for EVERYTHING wrong that happens...partially the reason I don't play it much anymore
Those are all download games--for online games, I like tinywarz, now renamed to dropshock (www.tinywarz.com will still work). The doldrums have hit it, but it's still going strong...it is possible to get to the paid status somewhat easily with the game's in-game economy...recently unpaid users can pretty much do anything though.
A looong time ago I played Nodiatis--not sure when, but most likely '08 or so, might be beta...I liked it, it's a little like WoW, but IMO better than runescape...there's just a lot more choices. Plus you get free xp/hour, even afk in 1 skill!... ... .. .... A downside is a free account cannot trade in any way--if you somehow manage to save up to buy a time card though, you can get a standard account, and depending on if you have anything to sell/your crafting skills, you could possibly remain on standard for free.
One game I really enjoyed is Pirates of the Burning Seas. You can download the game and try a free trial at burningseas.com. If you're looking for something free, this isn't your choice. But because it's not free, the quality is amazing.