Snag is that LCD is increasingly looking a better bet; you can buy a decent 30" set for £2500, and I expect to see them at around £1500 next year, maybe less, and the quality and resolution is generally much better, plus you don't get station ID logos burning in. By this time next year there may be affordable (for me) 40" panels.
I'm ruling out projection (expensive, noisy, huge power consumption and hideously expensive lamps), projection TVs (too big, and I couldn't place one where I want it over the fireplace), and bigger conventional TVs (see above). So the question is...
Should Marcus Spend Huge Amounts Of Money?
Yes, you want plasma now, go for it!
No, wait a while and see what happens.
No, be happy with your existing TV and give the money to charity
No, TV rots the brain, smash it and read a book.
All comments gratefully ignored (or not).