I set up my Panasonic 54" 1080P Plasma as a computer monitor specifically to try it out in my TV room. I wanted a huge monitor in front of me. I used wireless keyboard and mouse to get some separation.
The plasma nominally has large advantages over a typical LCD. Blacker blacks, far better off-axis picture, faster effective refresh, often better color. One technical downside a tendency for "burn in" of bright images that sit in one spot on the screen for a while. The burn in is not permanent in normal use. Rather, there is a slightly lighter area on the screen for some minutes -- usually, these days, its only visible in a dark part of the screen in a dark room (as plasma technology now has features to minimize "burn in"). LCD is also capable of burn in but its less obvious because LCD contrast is so poor to begin with.
Main Advantage/Disadvantage is that they don't make small ones. The games did look/feel much much better that size in front of me. However, unless I sat about 8 feet away, the pixels were too evident to my eyes.
All in all, I seriously considered it, but as I was going to buy another one for a desktop and couldn't get a small one, it didn't work out for me. I went Eyefintiy.
Not stupid to consider it in a "man cave" -- particularly if you'll be sitting a few feet from it, I think. Heck, if you own it and its already set up, use it until it "turns you off"

_________________________
ATI Sapphire HD7970 OC - Eyefinity 5760x1200 24", 1xDell-U2410 H-IPS + 2xHP-ZR24w S-IPS, Extended 23" Samsung cPVA, Ceton InfiniTV 4, Bulldozer FX8150@4.5GHz w/Swiftech Water Cooling, 16GB GSKILL PC3 @1866, ASUS Sabertooth 990FX, Corsair 120GB SSD, WDigital + 3x Seagate + Hitachi + 2x WD Ext = 10.0TB, Sony DVD, OCZ ZX 850W PSU, CoolerMaster HAF922, TM Warthog HOTAS, TM T-Flight Stick X, TM Cougar+FSSB & CH Pedals, Saitek X52 Pro & Pro Combat Pedals, TrackIR5 w/TC Pro, Windows 7 HP 64b