Support your local record stores.
That's all well and good but the majority of the buyers on iTunes probably aren't there for a full album. Most likely they purchase a few single songs at a time. Unless my local store is going to start offering that, preferrably in a digital medium so I can save myself the clutter of unused CDs, tapes, vinyl, etc. I'm not buying.
Let's not mention the difference in available selection. Not only is there a huge selection of artists from the major labels there are also indie artists on iTunes that you can't find anywhere else unless you make it to one of their shows (look for Jak Locke as an example).
Then there's the shopping experience... I'm sure there are people who enjoy pouring over record after record after record in a store but that is the minority of music shoppers. Plus with brick-and-mortar stores there's the wonderful variable of human interaction. Every shopping experience I've had with a local record store has been ruined by the employees.
Local stores will always have a niche so long as real-media music is published. However, they will never be able to capture even the smallest percentage of the market in today's convenience and selection driven economy.