All three technologies have different strengths and weaknesses, and the economics of their production is such that their relative value (or even availability) will differ at different diagonal sizes.
On the plus side DLP, like LCD, is immune to burn-in, as plasma is not, and, IIRC, uses less power than plasma. (But probably somewhat more than LCD panels.) Also a panel LCD (as opposed to LCD rear projection) is probably is probably more expensive at that size than either plasma or DLP, which probably makes DLP the best over all price/performance choice at the size you're interested in. But ultimately it will be up to your perceptions and what kind of material you watch.
I'm replacing/upgrading TVs as part of an overall rennovation of my condo. I needed both a smaller set than you're looking for (a 32" to serve as both an HD TV and a PC monitor in my home office and a 56" for my home theater.) So I went with an LCD for the home office, and chose LCoS (a JVC D-ILA set) over DLP for the living room because I thought that was the best value and most pleasing image in that screen size. The sets will be delivered the second week of December, after the new flooring arrives and the place is painted. I can hardly wait.
Regards,
Joe
