Ok so first off,
everyone is going to have different experiences with different projectors.. I have had two, my first one was bought in 2005 and is still running very strong. I paid 2,800 for it on bestbuy.com, and just recently saw it in a best buy ad for 699.00 Since 2005 I have had to replace the bulb ONCE. I bought a warranty for 350.00 and essentially it paid for the bulb. Since the warranty is 4 year on top of the manufacturers first year, it is covered until 2010. I use it around 20 to 40 hours a week. I absolutely love mine.
In fact everyone I hang with now loves my projector so much they all have gotten one too. Well three of them at least. BUT heres the catch. My friend bought one and it has been a piece of junk. So id say read a bunch of consumer reports and customer reviews. As for tech stuff get the highest contrast 10,000 to 1 type stuff you can, and stay away from anything under 2,000 very hard to see. Mine is ok in daylight, but with the light on its very faint and hard to see. these things are meant for total darkness so keep that in mind. Essentailly have a Entertainment room just for it. As for screen vs paint, I bought that 14.00 reflective gloss recomended for projectors and it worked amazing. With the light on you cant tell its there, But when the light is out and the projector is on you can see the edge of where i painted. Screens are relativly cheap though .. hope this helps, message me if you have any questions..