No experience with Toshiba but I definitely would buy an Asus. Personally I'd be a lot more comfortable buying something from NewEgg than Best Buy, although I'm not sure how much that matters WRT whole computers.
If your computer stops working due to a hardware failure, I don't know what Best Buy will or won't do about it. Maybe they'll handle the warranty stuff, maybe they'll charge you some kind of diagnostic fee. Probably there is some kind of policy on this, but I don't know what it is. But if you're not comfortable dealing with someone over the phone, having gone with an online retailer would be a problem.