Here is my list of online auction house alternatives. I'm purposely leaving out the obvious - eBay, Amazon and Yahoo!. Opinions are my own, naturally.
SellYourItem Been around awhile - at least a couple of years - and still hanging on, SellYourItem is a reincarnation of Gold's Auction, which was founded by a disgruntled eBay PowerSeller. SYI has a core of faithful sellers who have stuck with the site since its inception and continue listing. Biggest plus is that, last time I checked, listings were free to insert (fees charged only with a sale), and sellers can choose a 30-day auction length with up to three autorenewals, allowing them to list and then forget about it for 4 months. Seems to have a high proportion of international bidders, which to me is a positive.
* Update * SellYourItem is shutting down as of February. Announced the same day I posted this plug.
Overstock Auctions Launched autumn 2004, Overstock's new auctions area is showing great promise. I personally like Overstock.com and have ever since I learned how much the CEO's heart is in encouraging native economies, arts and crafts (check out the Worldstock section of Overstock proper) and ever since Overstock ran a free shipping special to service people in Iraq and Afghanistan (probably no longer running but I am not sure). Overstock has the capital to sustain the initial launch time to get an auction house running, so I have more confidence in its staying power than many I've seen come and go. Plus it didn't hurt that an Overstock rep called me personally to announce the launch and invite me to list. Flattery will get you anywhere, baby. Oh, and another thing: I emailed a technical question through their help option very late one evening, and when I checked email first thing the next morning, I found not one, but two, personal responses, and my problem was fixed. How refreshing.
WagglePop A new startup from another disgruntled eBay seller, scheduled to launch in February 2005. Lots of initial interest from sellers. Whether the buyers will find it will be the big question. I am personally underwhelmed, so I hope WagglePop proves me wrong.
AuctionFlair Still evidently in the very early planning stages, AuctionFlair is (yep, you guessed it) the baby of yet another disgruntled eBay seller. I know nothing of it except that it is "accepting reservations for userIDs" and is putting together an informational email list for an upcoming launch. If you sign on, use referral twinglemimi+1, the lady who referred me there. (I don't need the referral.)
And lastly, OTWA Auctions I have high hopes for this one, as it is the brainchild of such wonderful people - Jim and Crystal of Online Traders' Web Alliance. I am anxiously awaiting what they come up with. Have a look around the message board and see what you think.