What Is the difference between Blu-Ray and HD DVD?

I just got a PS3 and I do NOT have an HDTV, so if I bought a Blu-Ray/HD DVD, would it still sound like an HD DVD without and HDTV? Plus, what is the difference between Blu-Ray and HD DVD? Thanks!

Related posts:

1. need help buying home theater surround sound?
2. Whats the difference between LCD and Plasma Screen TV’s?
3. What is the difference between blu-ray dvd and hd?
4. what is the difference between blu ray and dvd?
5. whats the difference between a hd dvd player and blu ray?