Yeah Chop I think you are going to just have to figure out what is most important. The HD5 apparently is true state of the art home 2D. So you can light up that screen and enjoy 2D Blu Rays to their fullest for years to come. Just MAKE SURE you don't care about 3D or would be wishing you had the option to show that off.
As for 4K.... my guess, and opinion, is that we aren't going to see any reasonable amount of good 4K content in any form for a few years still. Maybe 2 years at the earliest for there to be widespread availability of some sort of content service with multiple studio support, and at least that long or likely longer for a disc based 4K unit to come out. What you get NOW with 4K is the complete disappearance of pixels from any seating distance at any size screen. This is the worry for me. Once I get a chance to see a DLP on a 160" wide screen I can say more on that.
So I think the real candidates for your dollar are still:
HD5: for best / brightest pure 2D experience - Jeff has a good point about technology being its best right as the next "new" thing is coming out. This is a good example. Apparently terrific custom 1x1 support from both Dan and DD on this unit as well.
DPI Highlite: for a similarly priced unit with about the same brightness, and with 3D added. Also a little quieter. Dan has pointed out that you give up 2D quality in the color and optics to go with this unit.
DPI Titan: Pay a good bit more, in the low/mid 40's range street, and get back most of the 2D quality with very nice optics and better contrast while also having state of the art 3D.
Or the Sony, at half the street price of these, but with substantially less brightness. I am not sure you would like it on a 16ft wide screen, but I think it is still brighter than almost all projectors of any kind that are near its price range. I don't know what screen material you are going with, though. As long as its at least a 1 gain screen you might be relatively OK. Given the PJ you mentioned you have used in the past, I assume you are pretty used to ftL readings in the 10-15 range at the most, so you wouldn't feel let down by going with something in this range again. The Sony gives a likely bit of future proofing (depending on what they do with the upgrade of the unit to new "secure" 4K standards), and you would also know you would never see the pixel structure.
BTW.. my Sony has been sold now, so don't feel you should take my Sony comments with a grain of salt.
It really is a great unit, especially for the mid teens.