Kind of too broad of a question. I'd think it would depend upon the level of the client. Also, do you mean affiliates or true clients?
If the latter (clients) then I'd say anything from a gift certificate to Amazon, to a Honey baked ham or a nice shipment of Omaha Steaks or something comparable. It's not the monetary value that matters here, but more of the sentiment that says "Hey, I really appreciate your business!"
Affiliates are a little different, they are more greedy so to speak. Gadgets and monetary rewards likely are more appropriate here. Here the gifts/rewards for successful contributors to your business is likely higher in value to you - so the ante goes up. Tickets to conventions, hotels, airfare, etc. kind of things come to mind atm. Doesn't matter really how successful that WM might be, sparing costs to attend events definitely helps out the bottom line. In the gadget department I'd focus on tools that can be used to continue their biz on new levels - PCs and other hardware. I have no use for another DVD player but I'd certainly love getting a new computer to expand my LAN here.
just doing some free thinking...
