I vote against Steinbart's. Last time I was there they were scary expensive, the employees seemed bothered when I asked for a couple items that were behind the counter, and the serve yourself grain area was a disaster. I really feel like the only reason people go there is momentum. Oh yea, and if you want carafa you can choose from... carafa. No special, let alone the 3 different varieties of each. Same story with caramunich. And they don't put the maltster on the bin labels. And they don't carry multiple maltsters in the specialty grains. And I could go on.
It's very much worth the drive to go to Brew Brothers. They're incredibly helpful, and have great prices. Also, they have an enormous grain and hop selection, and they'll never have a problem opening a bag or packaging some hops for you. They run brew demos on Sat and Sun, so it's a great time to go hang out and see the process or ask for tips. They also make deliveries around town, so you can call or place an internet order and pick it up somewhere closer to home. Check their website for the info.
Main St. is ok too, but they were more limited on grains and less helpful than BB the couple times I went out there.
BTW, I'm in no way affiliated with BB other than being a very satisfied customer. They're just my favorite, so I gotta give them some big props and keep them in business.