Number of watchers isn't really a guide to how much it'll go for, but it is reassuring that people interested (and at least you haven't mistakenly put you bike bits in the pottery and ceramics section of eBay).
Crazy as it sounds I've often see the low watcher count stuff go for more as you get two people who definitely want it and try to out bid each other.
I tend to watch stuff I wouldn't mind if they go for bargain prices, but unwatch when price gets too crazy (as per usual on ebay...).
Good luck, keep your nerve until the last few seconds, it'll look like its going for pennies before the sniping starts at T minus 7 seconds!