Bundling vs not bundling depends on the items. In my experience, bundling works best, if one of your items is highly desirable and will make people overpay for your other items, or if your items are usually bought together as it reduces uncertainty and hassle for the buyers. It is least likely to work if one of the items is a niche item that is mainly bought by people who already have your other items. In any case, it is a good idea to do a rough calculation based on the sold items on ebay.
I have had some "bad" experiences where buyers have returned items with the excuse that they were not as described. You lose the shipping cost, but I just write that off as the cost of doing business on ebay. Check out other forums or message boards, too. GetDPI was mentioned, or target a particular buyer group as Keith has suggested. It may pay off, especially given the ebay fees, but you may lose whatever seller protection ebay offers.
If you decide to sell on ebay watch the market for a bit. It seems that some items come on in waves, and you don't want to compete against too many other sellers. Have a starting bid you are comfortable to sell at, and you should be fine. Personally I would avoid the invisible reserve price. If people are bidding incrementally, you might not sell an item that would have sold with an equivalent starting bid.
