All things being equal, i.e., similar quality sets overall:
Bright, reflective room: LCD wins (assuming matte screen)
Off-angle viewing: LCD wins
SD content: DLP wins
HD/Blu Ray content: toss up
High motion content: DLP wins up until recently, but newer LCDs (120Hz) have got excellent motion handling capabilities
Inches/$: DLP wins...you can get more screen inches for less money w/a DLP these days
Obviously, LCDs win on thinner form-factor, more flexibility in mounting/stand options, and probably have overall better relability long-term.
I have a 65" DLP and 46" LCD. DLP is in family room, 14' to 16' viewing distance, and it's big, but I wouldn't mind a 73".
On bright days I often wish we had an LCD in this room...the sunlight can wash out a DLP easier than an LCD.
If you have the room for the set and the viewing will not be from wide angle, a DLP offeres a lot of bang for the buck these days. At your viewing distance I would want at least 60" of screen, and that's a pretty penny right now for an LCD.
Oh - one more emphasis point. The one area where my new LCD (Sony KDL46Z4100) really falls down is SD content...it can go from good to horrible, depending on the source, while the DLP is much more forgiving of poorer SD feeds.