No, plasma does not have a "short" life expectancy (unless you consider watching it 24 hrs/day at cranked levels for several years short). Even given that, I still tend to advise against plasma - generally higher electrical costs, noticeable screen-door effect (at least for me, including Panny PX TVs) etc. I do like the Pioneers but prefer more for the money.
Truth in advertising - I bought a Samsung RPTV @ CircuitCity this September (tremendous price, plus picture to match). I spent literally months researching but then the deal popped up out of the blue and I acted. My son bought a Samsung LCD - much better IMO for use as a computer monitor, but the RP still works just fine as a 1080 monitor too (except I see a very slight blurring in the remote corners, but I haven't bothered to do extensive calibration yet). The Samsung 120Hz LCDs are noticeably better than other/lesser refresh LCDs at motion (sports, etc.) to both our eyes. The LGs and some other brands are quite decent, too - but I'm hooked on Samsung now.
As far as the plasmas, don't worry about life expectancy - seriously. Do look closely to see if you're bothered by screen door effect (I could not tolerate 720 plasmas because of the effect). Do your research, and you too can wind up with a spreadsheet that shows many plasmas (well, except for the PZ800U) have up to 3X the annual energy cost of a Samsung LN52A650 (and do your own numbers for the LED source models). That LN52A650 is a very fine unit and highly recommended (and what I'd have gotten if the RPTV number that Labor Day weekend wan not quite so spectacular - thank you coupons & cash-back).