The Doctor has two main suits: brown with teal pinstripes, blue with red pinstripes. Each one has a variety of shirts and ties that are worn with it. This page has various looks with the blue suit. To the right are all the elements present in each look, so I don't get repetative here.
The Doctor's blue suit is my favorite. At one point I was determined to make it myself. Then I realized how complex that would be, while Magnoli Clothiers makes an amazing replica suit. Why reinvent the wheel when I can simply buy it?
Why I chose this costume
To be honest, I'm not exactly sure why I wanted to do the "dark" look first. I think it's because I love "Silence in the Library/Forest of the Dead". It's also a more distinct look for him; one that you don't see often.
I found a tie on eBay that has a very similar pattern, and was black with an ombre red and silver design. With a little bit of patience and red Sharpie, it became a red design.
For now I'm using a black dress shirt I already have until I can find that right shade of dark maroon to be accurate.
Version: the "Dark" look
Source: Doctor Who episodes "Last of the Time Lords", "Time Crash", "The Unicorn and the Wasp (flashback)", "Silence in the Library/Forest of the Dead"
Not Yet Worn
Dress shirt, black
Tie, black with red floral - eBay