Robber - 9:29 am on Aug 18, 2002 (gmt 0) Probably a few more too, I'll have a think.
I would say:
*Range of graphics - not just 468*60
*Marketing copy - and let the affiliate customise it a bit
*Products that actually convert
*Competitive commission rate
*Plenty of affiliates like a long cookie, but Im not so sure this makes a whole lot of difference
*Deep linking - this is a biggie - especially if you can provide a spreadsheet containing all product details, including reviews, urls image urls etc.
Probably a few more too, I'll have a think.