PLASMA VS LCD?

first, led/lcd televisions use the same panel technologies so they are the same. the only difference being that led using led backlighting while normal lcds use ccfl.

between edge-lit lcd and normal ccfl tv designs there really isnt an advantage. i have noticed that on some newer tvs with a "grid of leds" behind the screen that strategically turn on/off contrast can be improved eliminating the "dark grey" instead of "true black" that plagues lcd technology (due to the backlighting).

if i remember correctly plasma televisions will have deeper blacks than lcd and again, if i remember correctly have a better contrast ratio.

however, plasma televisions just dont seem to hold up. a relative was in television repair and always remarked how often they needed to be fixed and how expensive it was to get them fixed. unless you're dead set on plasma i'd get lcd.

most of the newer ones look better to me in terms of contrast/deeper blacks then the one i own which is about 3 years old now. go to a store and visually look at them yourself and judge.

^You said you got a 1080i TV, no point in getting a blu-ray now...

depends on the frame rate scaling of the video processor in the television (or in the receiver)

if your television can take 60 frames per second and upsample (as well as interopolate) the interlaced signal.. the progressive frame rate would normally be 30.
but
with the upsampling, new frames would be created from 'key frames' and bring the frames per second back up to 60.
technically.. the television would be working at like 120 frames per second interlaced, plus or minus any frames to help create the upsampling.. that is much more of the reason why the new televisions dont play well with live video games.
'key frames' are plenty enough to get the same exact content viewed live.. regardless of the frames per second (60, 120, 180, 240)

but remember this..
you should only DOUBLE the frames per second.
if you try to triple the frames per second, the video processor will get confused inbetween key frames and ugly things happen.
could be a crash of the video processing..
could be an artifact visually seen of the video processing..
could be a nuisance that interferes with the inputs and the mental receiving of the synchronization for input to visual result.

a 1080i television can produce 1080p with full frames per second, or half of the frames per second.
hell..
the televisions can try to triple the frames per second and see stupid results (accompanied with a high lcd panel response time and the results really are seen as stupid.. or 'dull and lifeless')

I like plasma's and acknowledge that they do produce better contrast and have better view angles...

BUT

after putting in a little monitor in my outlet for my plasma's...which is a 50'' samsung 1080i, it pulled a steady stream of 600watts out of the wall, not to mention the screen was giving heat enough to make the room a few degrees hotter. I can't even imagine how much power my other 64'' 1080p takes up. Not to mention how much heat it gives off. Im seriously considering getting rid of both and getting led-lcd's or projectors, not really because of power but because of the heat they make, i don't like it when it gets hot.