I'd say both,
But my angle would be to use ebay as a marketing tool to get people to your site. most ebay users looking for a product to buy online will go to ebay before even going to a search engine. If they buy from you as an online store through ebay, chances are good that you'll generate a lot of repeat business down the road through your ecommerce site... especially if you offer incentives like sales or breaks on shipping. it saves you money on final value fees too. I'd say start with ebay and ecommerce and fade out ebay.
We all know that in 5 more years ebays prices will be comparable to the real world anyway.
Good luck!
-Clint
www.spacemanxpress.com (ecommerce solutions!)