If your PC does what you need it do it, and fast enough for you to do that work/task/game, then there's no real need to upgrade.
Do you have a particular game in mind Corrugated?Some of the modern games are very demanding, and you may be faced with upgrading gfx card, cpu, power supply and RAM. You see where I'm going with this?I play a lot of Quake 4, which to be fair is one of the most resource intensive games out there, and after upgrading gfx cards etc, eventually realised that the machine was never going to perform like a modern dual processor, high spec machine. I went to dell and dispensed with anything that wasn't game related, so I have no speakers, didn't get a mouse and kb (as I have gaming gear), one basic DVD drive, the cheapest OS on offer, no AV software etc, and that kept the price quite reasonable. It is however only good for playing games!Whilst I hate to suggest it, you might be better off buying a new machine, if you want to play the latest games. I offer this only as my own experience though, I'm not an expert in these things.
(flak jacket on) Stay away from the Dell Dimensions. They're nothing like they used to be. They're just cheap, limited PC's, IMO. Myself and my tech buddies have worked on them enough to know. HP's are alright, or you can piece your own PC together. Newegg.com is among the best PC sites with very respectable prices. It depends how PC/tech savvy you are. You might be better off going with a pre-configured off-the-shelf system. Let us know what you're looking at before you buy anything.
What's you opinion on Gateway?
I have a high-end Asus mobo, Corsair ram, Sata drives, 550W psu, but my 6600GT agp video card died on me months ago. When I recently looked around for a replacement I couldn't believe how expensive agp cards are now, not to mention getting scarce. Now I'm using my onboard video and though it sucks I won't upgrade further on this machine. My next PC will be cutting-edge technology at the time of purchase.I agree with what Whoey wrote. If your PC does what you need it do it, and fast enough for you to do that work/task/game, then there's no real need to upgrade.