Subjective....perhaps shop is better than store. Google shows more matches for "shop" compared to "store" (although hard to know the context of all those matches). On Overture, the numbers are roughly the same without the .com, and with the .com shop.com is ahead.
Interestingly, though, "store" is a $1.43/click keyword on Overture, whereas "shop" is only a 28 cents/click keyword.