Two Plus Two Older Archives - What computer should i get

I'm going to buy a computer primarily for poker some time in the next month. I don't know a whole lot about computers though and i was hoping to get some advice. I want one that's reliable and would have no trouble 4 or 8 tabling on party while listening to music or using internet. I would also want one that has the potential to hook two monitors up to it. Do you think a Dell would be a good way to go, or should i have one built at a computer store? I was thinking 512 or a gig of ram would do the trick, but i was wondering if having two monitors hogs extra ram. I also wanted to get a decent monitor 19 or 20 inches, is there one out there that's better than the alternatives? I'm just going to buy one monitor for now, and maybe get a second later. btw my price range for the whole thing would maxes out at around 1k. thanks for any advice