Th "opinion" of the "tech" at Circuit City shoud be taken with a grain of salt. The Intel chips right now are faster than their AMD counterparts, but that doesn't mean AMD chips are bad. I've used nothing but AMD CPU's in all my builds and have never had a problem with them. They are a great solution when building low cost computers and also do well in a gaming machine.
Now, if you're wanting to build the absolute fastest, meanest, gaming computer you can get your hands on, then an Intel based system would be the way to go. But since you're just looking for a good all around system, the AMD system would do you well.