Ryzom

pvp is by both accepting a challenge, there is also a pvp zone in one country.

dont know about the sys specs but i got a 2.4ghz amd, 512mb dual ddr 3200, gf4 mx440.
it runs without lag at mine, but i would recommend more ram... iv heard about guys with 1ghz running the game lag free with some tweaking too

I recomend a gig of RAM as well(seems like all games need it now days)

I reckin a card with T&L with pixel/vertex. and about 500-1000 ram. B/band natch. The world is huge, densly populated and graphically beautiful, so take it from there.