I have a Dell Dimension 4600 w/ a P4@2.4Ghz, 512 Mb RAM, 80 Gb HD, and a nVidia GeForce 5200 FX gfx card running M$ Windows XP SP2. I run software like photoshop, 3ds max, Guild Wars, Halo, UT2K4, and other editing programs/games. My computer isnt really slow at running these, but id like them to be a little more fast/efficient w/ them. Which hardware should I upgrade first to receive the best performance increase(within a reasonable price range)?