I am absolutely shocked that nobody said "upgrade the frame first"

There used to be a lot of Langster hating going on around here(admittedly I was one of the haters) but you do have a decent frame. If you have the upgrade bug(which we all get eventually) I would suggest looking in to upgrading the wheelset. While I do not have any direct experience with the Langster I have hung around here long enough to see a lot of Langster owners who love their bike but hate the stock wheelset or at the very least have had problems. A lot of folks say in the roadie world that the most noticeable upgrade on an inexpensive bike is a nice set of wheels.

My $.02