First of all, the best time of day to post greatly depends on what you are selling. I sell mostly clothing, so we will dig into this category. The following will probably not work as well for say- antique paintings.
1. I can not count how many posts I have seen stating that Sunday is the best day to end an auction! Either you can make a seven day listing on Sundays to maximize your sales, or "start a 10 day auction on a Thursday." (Mike Steben, 2010) The 10 day duration will give you two weekends to maximize your views.
2. to end mine between the hours of 8 pm and 10 pm CST".
-Many Ebayers agree with this time- mostly because this is when everyone is settling in and relaxing in their "Me Time".
3. "I've found that many of my buyers are using sniping tools so they just bid what they feel the value is to them and don't worry or care what time it ends, about staying awake or even watching the auctions"-
4. Some believe that there is no "time to post" that will get you more sales. not convinced that there is a best time ... Bidders can use the search functions, as well as browse and if you have items that are well described at a decent price - they will find your listings".
-I think I agree with this opinion above the others. If your item is in high demand, it will most likely sell; of course, it is up to you to optimize its keywords, photos, and description!
No matter what you read- the best way to find the best time to post on EBay is to experiment yourself!
Play around with Auctions, times, Buy It Now, and keywords until you find what best suits YOU!