Im going to recommend if you want a MMO, specifically, a large expansive world with lots of people roaming around, then dont play Guild Wars. (Also the fact that you basically need every expansion at this point).
The "heroes" that they implemented (NPC minions with customizable skills/armor/weapons) is actually pretty good, in theory. In practice, while PvE w/ heroes is almost always preferable to pve-ing with a PUG, the general rampant stupidity is magnified by the fact that the game is NOT solo-able. Except for the little beginning part of the first game, no class can solo everything. Also, the pve economy is completely fucked up.
For a pvp game, its actually quite good, however, the learning curve is pretty steep, and getting in with anyone who matters is a challenge unto itself. Also, if you want to pvp on any sort of higher tier level, you basically need every expansion pack (original + nightfall + factions + northsomething-or-other).
Keep in mind that last I played was over 2 years ago, I quit because the game stopped offering anything. I got my Rank 9 tiger emote (you can get glowy animal emotes for doing well in the open tournament style pvp), and I spent a couple weeks in top-ten gvgs. After that, well, there really is nothing else. Sure theres some titles you can attempt to farm out, but... whee?
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WAR has been pretty fun, but not without its launch issues. But I kinda expected that. I have to say, the fact that you can start doing scenario pvp basically right after you make a character (and not be 100% useless) is pretty cool (scenarios buff you to their level tier, so the first tier will buff you to level 8, and up your weapons, armor, and stats accordingly, however you will not get any of the combat skills you dont have yet). So yeah, leveling up in pvp is pretty slick.
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I can recommend avoiding Silk Road, besides the fact that its a free korean(I think?) MMO, it has numerous issues like: Pointless "careers" (thief, merchant, merch defender (or whatever its called)), AMAZING amounts of grind, and a stupidly complex learning curve (Seriously, nothing tells you that you should only be putting skill points into like two things, or that you can farm the shit out of skill points for bigger bonuses). Oh, and the pvp is somewhere between non-existent and pointless.
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Also, Your vid card should handle most anything out there right now. You might not be able to max out graphics, but I dont think theres anything out right now that requires more than you have.