I always try to end my auctions around 3-4 PM PST. I was told several years ago that statistically speaking, that is the best time to do it because, believe it or don't, "most people" ebay from work in the afternoons just before quitting time.

Of course, more companies these days have websense or the like, as mine does, and prevent people from accessing ebay. Also, like I said, it was several years ago...and demographics and statistics tend to change over time, eh?