Hairsonfire (great name), to hear that you've had your DLP TV for three years and you haven't yet had to change the bulb is not only a slap in the face of some DLP TV haters here, but is encouraging to the rest of us who DO own DLP's.

To answer your question, if your HD TV broadcasts look fine then it's not the bulb. You don't indicate whether the discoloration occurs with Blu-ray movies, HD-DVD movies or both, but I'd be suspicious of the movie disks you're playing first.

Hope that helps some.