Reputable = Panasonic, Sharp, Pioneer, and Samsung (I got a defective unit, they replaced it).
I heard Hitachi has a horrible customer support.
On Sony here's my opinion
50% Cable ...hmmm they say Plasma is better for cable, but because cable is 4:3 and the TV is 16:9, you will display at 4:3 with black bars left and right. Given enough time, it's possible the black bars will burn-in. LCD doesn't have this problem though. You'll have to check with plasma owners on this.
Reasonable = nope.
Check the internet, for prices overseas.
It's expensive here. But it's ultimately to your best interest to still buy it here.
On your wants
1) PIP w/ 2 tuners
----- (not sure why you would want to watch 3 shows at the same time but to each his own)
2) 2 or more HDMI cables
------ I am guessing 1 for a game console, another for a DVD player... If you need to buy a set with 1 hdmi only,
component will do the job just fine. Hard to notice any difference on small screens (40" and less)
3) Reasonable contrast ratio
------ For better contrast, they say plasma. I'm totally satisfied with the contrast on an LCD...just need to
calibrate the TV properly.
4) Future proof (at least for the next 3 years)
------ A TV is a TV...whatever you buy now will still do the job 10 years from now
Even your CRT will do the job 10 years from now. Whatever you buy now, was really created 5 years earlier.
New technologies to watch out for: LED TVs and OLED TVs.
5) Fast channel surfing
------ No idea here... I only use my TV as a video display unit (DVDs and PC)
oh and on games... you can't use ordinary light guns on plasma and lcd. There's an alternative you can purchase on the net, but only good for one player.