ext3, xfs, or reiserfs, 200GB or 400GB?

[Berserker]

if you are using the data over the network may be worth your while investing in a newer board, as built on network cards sit on the pci bus.

I use a heavily-optimised Gentoo installation, which limits my options a bit. At some point though, I'll probably get an A64-based board and hope for the best (won't have 64-bit support, but at this point that's not a huge deal). I should really get a move on as I'd rather have an older board and save myself some money. Having said that, DDR2 isn't that expensive.