I used to build all my bikes from scratch, piece by piece. While it is fun, after a while the headaches incurred aren't worth it and box built bikes become more and more appealing.
My next MTB is going to be ordered from the factory because even with a dealer discount, buying a complete bike is almost 3x cheaper than buying the parts individually.
The same wasn't true w/my fixie, though I used a lot of used and circa 1980s parts which lowered the cost. I did have a lot of redundant costs too, as in having to buy 3 or 4 of something, or ordering the wrong parts on accident.

BTW, I sell the langster, Pista, and the bowery at my store. The pista wins hands down in terms of value and styling.