Boys boys boys.
When you install a projector, you will quit measuring in diagonal inches and start measuring in horizontal feet. My HD picture in my basement is just shy of 10' wide. Can't remember how tall it is, but shouldn't be too hard to figure out. 16:9 screen ratio.
My problem is the cost per area ratio. Sure you can get a massive picture with a projector, but all of them that I looked at that I thought were good ones, were in the $7k-$10k range. I paid $2k for my tv. They've probably come down in the four years since I bought my tv though. So maybe they're worth looking into again. Especially since the room it'll go in my basement will be cave dark.
