It's really hard to recommend any specific MMO game, because everyone likes something different. A game I like you may hate. Check out http://mmohut.com
for a large list of these free mmorpg / mmo games. I use that site to find new games to play. Every few days I try a new game :) - It's a lot of fun because I try everything. They have like every single MMORPG categorized nicely with reviews, screenshots, videos and more. Heck they even list the game's system requirements!. Best part is all the games are free, which rocks.
They have a huge section for "no download" browser MMORPGs as well. All with screenshots and reviews!
Let me know if this helped at all!