Tekserve on 23rd. http://www.tekserve.com/ which specializes in macs but has a ton of stuff. The staff is very knowledgeable if you are willing to endure the condescending tone of a nerd/hipster. I find the prices are about at what you'd expect if you went to the apple store or directly to a brand store with rare discounts.
And the second, which is my favorite at 34th and 9th. http://www.bhphotovideo.com/ They have everything. The staff is knowledgeable. Only check their hours. They close early on Friday's and I believe they are closed all day Saturday.
