First, they have more than one shop. http://www.greggscycles.com/cartgenie/new_loc.asp

As for bike shops I really like recycled cycles for a lot of things. If you want a cheap used part, are looking to replace a random missing part, or are looking into something like a bike build rebuid ect I would go there. I have gone there for a new set of cranks for my commuter. I wanted to try 170mms before I commited a lot of money to them so I picked up some for 5 bucks. I like them now I can go out and buy decent ones.

I have had mixed experiences at Gregg's. One time I went in there for a tire and a basic seat for the GF. I talked with the guys for a while about bike things and they showed me the shinny new FSA carbon cranks with ceramic bearings they just pulled out of the box (I believe the retail on those was 2k). Overall, they were very knowledgeable and offered a LOT of information. On the other hand, I went there looking for a new bike and was less than impressed with the knowledge. It is a big shop some know what they are talking about some don't.

That is pretty much where I go...