eBay could be the perfect place to sell used electronics. The problem is the way they handle auction / buy-it-now listings.
Suppose you have a used Dell-brand server. You know that almost nobody is going to spend more than $800 on it, because for that money you could buy a new model. On the other hand, you figure someone out there might spend $500 on it because they're nearby and need it ASAP. And, you're willing to let people bid on it for a week and get it rid of it at the end of the week.
You can't accomodate all three parameters at once. If you set a reserve price, then once auctioning hits that reserve, then the buy-it-now is killed. On the other hand, if final bids are less than reserve, then the auction is effectively cancelled, and you're stuck holding the item.
Until eBay changes this, it will remain a non-ideal place to sell old IT equipment.