personally, i find it hard to recommend LED's, so i'll just assume that if you're considering one, that you are not as bothered by the uniformity issues as i am.
with that out of the way, there's only two reasons (i can justify) to get a projector
1) to go bigger. and 100" will be a substantial improvement over 82". but i still think 100" is under-utilizing a projector. with those room dimensions, i'd start at 120" and consider bigger
2) to use an AT screen. there is a real advantage, both in audio quality and in aesthetics, to putting your speakers behind the screen
both of those are HUGE things if you're going to use them. but if not, it's kind of hard to justify choosing a projector over a flat panel.
a standard flat panel will be vastly superior if there is any kind of ambient light, or even a decent amount of reflected light. i wouldn't personally bother to qualify it as 'bright', if you watch with ANY lights on, the image quality of the projector will not be as good as a flat panel. it may still be very watchable, depending on the content, but short of some very careful planning and/or expensive ALR screens, turning on a reading light in the room can be the difference between world class plasma blacks, and discount bin lcd 'dark greys'. The ANSI contrast ratio on my JVC drops in half if my cell phone screen shines towards the front of the room(seriously, from around 200:1 to below 100:1)
don't get me wrong. i love the experience with a projector, and i don't think any flat panel on the market can touch what a projector is capable of. but it's about picking the right tool for the job, and if you don't plan to watch a huge image in a dark room, it may not be the right choice.
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1130K, 7.1/5.1.2 audio
Sources: HTPC, PS3, XBOX360, Wii
Control: Harmony One