We're currently in the market for a new desktop computer. It has been ages since I've been "in the know" about the best processor, how much computer memory we need, and all the other questions you have when purchasing a computer.
The folks at CompUSA at Palisades Center were by far the most helpful when we went looking at computers today. We were upfront with the salesman that we were not ready to buy, yet he took the time to explain the background of the new Windows Vista system, the difference between AMD and Pentium processors, and several other questions we had.
CompUSA will price match, which is always a good policy. I am sure I will go back to this store when it is time to buy, because we felt the salesman was actually knowledgeable (can't say the same for Best Buy and Circuit City!), and he didn't drop us like a hot potato when we told him we weren't buying yet.