Well I've been doing graphics programs on 320MB PC100 RAM for about 5 years. Photoshops, with Flash running in the background, and PSD files with 50+ layers (that's where it starts bogging down, layers and filters). Anything's better than that!
I'll have 512MB soon, and maybe another 512 for ~$40 or so. My ultimate goal is to have 4 1GB sticks, 1 for each slot of the new mobo that came in the mail today.