+1, I am curious too. Is it for fashion or for function (either answer is a-ok by the way)? What is the terrain like in your area, what do you plan on using your bike for?

The place I live is not extremely hilly or flat but I do appreciate having a range of gears to make my trips easier. I had my bike with me at the lbs and one of the younger employees told me that he converted to single speed because he didn't like reaching down to the shift levers, now that is sort of lame.

I agree that it's not blasphemy at all, but it is good sense to keep your old parts. Later on trends or your preference may change and you will be glad that you have them. Most of the stones get thrown when permanent changes are made to a high end frame and I tend to agree on that point.