Projector - Looking for advice


I need to replace my old projector. I am looking to spend less than $600 used. I want 1080. Are there any models or brands you could point me to? What should I be looking for? Brightness, contrast, DLP, LCD, so on. I do not want 3D.
I really appreciate your expertise.
Thanks
Greg
gdush
What is viewing evnvironement like? Do you need lights on in the room, or is ambient light? How big is your screen? What kind of screen? What are your applications? ..movies and tv only?..gaming? ...pc use?
HOw many hours at a time are you viewing? Do you need 30000 hour bulb cause the pj will be running all day and night? What did you have before - or seen before - that you liked? Any prefernces thus far?