My $0.02:
Get the RETAIL Athlon XP 1800+. It's cheaper than the 1700+ OEM and a separate HSF. It's only $4 more dollars and it comes with a heatsink and 3 year warranty AND it is more overclockable. The 1700+ has a higher chance of being a Tbred A, not a Tbred B.
I just noticed that Newegg currently has a bundle special. You can get the Athlon XP 1800+ retail and Biostar M7VIZ mobo for $99. Even more excellent!
You can get Corsair valueram DDR333/PC2700 ram for the one dollar less than the price for the crucial DDR266/PC2100 you were planning to get. There's no reason to get the older stuff, and it will severely limit any future processor upgrades.