As far as power consumption is concerned, the extra cost of LCD makes it an incredibly expensive way to save energy. Everything from solar to geothermal etc is massively cheaper per kWh saved / generated.
Bottom line on that one is I wouldn't even consider it an issue unless you're not on the grid and are relying on a limited power source.
I have a plasma. Main reason was for the amount of $ I was prepared to spend, LCD just didn't compare. Either much smaller, lower resolution or unknown brand for the same $ as a brand name plasma.
You won't likely have to upgrade a lower resolution TV by the way. You may want to upgrade in the future but actually having no option is unlikely in the next decade.
TV really isn't that important to me. So $1500 was the most I was willing to spend and for that I got a 106cm Panasonic with 720 lines (noticeably better than standard definition but not full HD). Bought it a few months ago.
Any digital TV, even standard definition, will give a massively better picture than analogue unless you have truly outstanding analogue reception. Apart from Tasmania where analogue is now in the minority, consumers don't seem in much of a hurry to go digital however. Last figure I heard was 28% nationally.