If you're on a budget, then you want some good, but cheap ram. I'd go for Kingston, Crucial, Corsair value select, Mushkin, or PNY, Pc-2700 and at least 256mb per stick. If you're doing some games, but you don't need ultra high end, then i'd go for a Geforce4 ti4200, 64mb or 128mb. There's like hundreds of versions out there now, and they go for about $120-160.
Instead of Rdram, why not just merge 4 Sdram channels...