Perhaps from afar, but the fun for me is looking for the unique visual cues that make each brand distinct.
There are many many places to find these, ranging from Hanes, AA, Uniqlo, and J. Crew to James Perse and D&G. Just do some research and figure out how much you want to spend.
If you really want off the rack, then I would suggest searching for Finamore or Barba on styleforum or ebay. Or you could spend $30 more and get Phineas Cole - they use a great collar in my opinion. Other than that I would just go custom through a reputable maker.