A lot of what makes having a fun space is actually getting to use it. But they should aso be multi purpose. Party basements are good. But having the chance to turn it into a theater are even better.
We have an Epson 8350 and I love it!
I've seen it on amazon for $1050 but we got ours for around $800 used. Only thing I can complain about is that it gets pixelated with fast motion scenes so I'd rather it be 120hz or something better.
We also picked up an Elite retractable screen with 1.1 gain so it wouldn't be as bright.
Just be sure you have dark curtains if you have any large windows or you can't watch during the day. For the basement this isn't a problem. It works great in low light but not in bright light.
The reason I commented about the 120hz is that when numerous pixels change colors quickly you'll see artifacts. Since it's 120" this will stand out much more than on a 60" TV. A faster processor and display capable of rendering at 120hz or more won't have artifacts. Many people don't like the "soap opera" look this causes. Personally, I want the best picture so I like the effect. Most sets have a setting to turn that off if you don't like it though.
That's my understanding at least. At 120" I think more that 60hz is necessary but this thing is great and I won't replace it until 4k led projectors are this cheap.
Keep in mind, this doesn't include your receiver, speakers, materials, this is just the projector. I think the total for the materials which included lumber, drywall, paints, etc was another $250-$300. It really wasn't that much total. I did everything on a lower budget so it looked good, but didn't cost that much.