I just can't wait to get my system. Do you think 512mb of ram is a standard yet? What is the ideal amount of Ram do you think...? I have 512, I have my whole system, I'm just waiting on the cpu, mobo and monitor to get here so I can finally use my system! It's mainly going to be used for programming and minor 3d design.
512Mb if you run it as a dedicated games machine or for everyday applications use.
1Gb if you have heavy usage, or wish to swap in and out between games and applications, without exiting programs. I use 1Gb myself, for my Games and household system, and 512Mb for this work system I'm on now.
I consider Windows XP to run like a dog on 256Mb or less, and would suggest that 384Mb should be the minimum amount used for that OS.