Jhuntley: About that low bid increment, it's good for lowering the barrier to a new bid, but on the last day/hour it leads to snipes. What if you kept your 50 cent increment, except right at the end of the lowball (last day/half day/hours?) and make it higher then, say $1 (or even more), so you encourage people to outbid other while the outbidding is cheap, i.e., before the end of the lowball? Of course they can always do a big outbid, just not sleazy last-minute small one which just forces anyone serious to wait around.
Another more drastic way of preventing sniping is to give a discount on early *winning* bids, e.g., a bid of a $10 that comes before the last day gets a 10 percent discount (say), but that same bid in the last hour gets no discount.