I don't eBay nearly enough to use a completely separate application just to browse through it, but if you do you'll probably be interested in GarageBuy, a free download from Iwascoding. They also make GarageSale, an eBay buying-and-selling program that I've heard good things about, but GarageBuy is committed specifically to browsing around eBay. If you want to browse for auctions without using eBay's old school (and frankly, clunky) interface, GarageBuy might be just the ticket.
They've just updated to version 1.1, with a whole lot full of new features. There's a new view that features a cool color-coded price tag (to tell you whether you're winning the auction or not), a countdown timer to show remaining auction time, and a slick little sliding thumbnail view for the auction's images. Plus, there's a whole bunch of other performance improvements.
And the best part is: it's all free. GarageBuy is freeware (and if you like it, check out GarageSale) over on the website.