I played Rappelz for a bit, and the game has no depth. It was interesting at first, but I grew annoyed after a month. It's not bad for being free, but it's irritating how people gain an advantage by paying. I rather pay monthly so everyone has an equal playing field.
"Jagex's browser-based MMORPG RuneScape originally launched back in 2001. The game isn't exactly hardcore. Like Sony's Free Realms, RuneScape
is geared toward a general audience, young and old."
AND... I quit RS for a bit and finally came back to it. The PvP is addicting. You can look at it and call it crap (because there is way too much grinding), but the boss fights and PvP is great. Basically Runescape let's you do skills (fletching, woodcutting, herblore, firemaking, hunter, runecrafting, agility, thieving, etc); so you can do the non-combat stuff and be a "skiller." If you want something a little more "hardcore" then you get your combat skills (strength, attack, defense, magic, range, prayer) up for some fun; PvP is pretty intense IMO. Runescape certainly doesn't have the graphics of other games (though there have been MAJOR updates), but Jagex has done an excellent job for having its game run in a browser.