The funny thing about Best Buy is people go there to test out items they're thinking of buying and then go online and buy them.
Personally I've had some pretty bad experiences with Best Buy including one that left me without a computer for a month and a half. Of course I bought a TV over Christmas break and returned two before I found the one I liked, and they made it pretty easy to do the exchange.
As for Crutchfield, I think Pwned is right. Their superior customer service is a big part of the reason they're still a powerhouse. It's kind of weird balance though, on one hand they tend to charge a bit more for stuff like TV's and speakers, on the other hand they also sell stuff like head units and amps at retail prices then include key equipment like amp kits and harnesses for free. Also free shipping is nice.
Either way, on simple plug and play electronics price is the biggest issue, with more complicated items customer service and support is key. Best Buy's biggest asset right now is the fact that you can walk into any local store and get what you're looking for the same day. However they're also getting beat by online e-tailers on both fronts (price and/or customer service).
Also Target and Wal-Mart are starting to catch up to Best Buy in terms of selection for retail electronics so that also plays a factor in Best Buy's recent struggles.
This story though reminds me of something I read a little while back.
Red Tape - A lost laptop, a $54 million lawsuit: part 2