Do an eBay search for Bulletproof Cranks.. the lettering is hella ugly, but it scratches clean off with a razor in five minutes (and it looks fine, no scratches in under layer of paint). The nice thing about the Bulletproofs is that they come in a variety of lengths, are really cheap ($20-25), and are shaped to hold one chainring only (mounted inner or outer), so the "spider" is nice looking.

Keep in mind that if you get updated cranks you'll need to get a chainring too, and that it should be the right size to screw onto the cranks (match the BCD, it'll be 110 or 130 or whatever). For a cheap chainring, go to www.danscomp.com, and on the last page of the "Chainwheels" section, there's a "Universal Chainring". They're cheap, but they cost like $14.

As for a bottom bracket, get a sealed bearing one, like a Shimano UN73 or UN51, 52, or 53. The 50s are cheaper. Make sure the threading and width matches your shell (68 or 72mm), and that the spindle length can give you the correct chainline.. might take some experimentation.

These are the cheapest options, and are what I'm going with.. they seem to work fine together. I got the black cranks, black chainring, black chainring bolts, and black eggbeater pedals, and they look sexy as hell.