Pros
The people you work with are amazing, many times you'll find that over time co-workers grow really close, 4 of my personal best friends are people I met while working at Best Buy. The discount is also very generous compared to other places. It also is a fast paced environment, so time passes very quickly. Best Buy isn't afraid to spend a lot of money on training you to be the absolute best at your job, so if you don't think you want to stay with the company you have many skills that can be applied elsewhere. The pay is above average for similar jobs.
Cons
Management often times are incompetent. The people making the descisions seem to have no clue about what goes on in the store. Many of the managers I have encountered have tried to demand respect instead of simply earning it, they actually know what they are doing, they just choose to stop when they reach management level. Promotions are hard to come by sometimes because of the structure of the store, at certain points promotions become harder to get because there is no where for the person who has the job above you to go, so you get stuck in the same spot for longer than you should.