For money, you can turn it into working hours. So the questions becomes - how many hours do I have to work to pay for this? I also typically assign different value to things which are reusable (like DVDs) versus something which is temporary (i.e. going out for dinner, or a trip). For some items you also need to include "care & feeding" costs (like car insurance, gas & maintenance).
Buy it.
Life is short.
Trust me.
The best investment I ever made was a $3500 57" digital TV . . . four years ago. The movies, shows, sporting events, and now X-box games I have played on this TV made this well worth while. With the amount of time I spend in front of a TV and the relative longitivity, it's a good investment. I would stay away from the LCD projectors though. Bulbs are very costly and you can get a better picture out of a big screen.