Up-Convert Player vs. Blu Ray

[merrim19]

Ok, give me a chance to explain because I think I have a legitimate question and I'm sure I'm not the first. I have a 37'' 720p LCD in the living room playing off of an up-convert player. I like the picture and have been happy with the LG player. I just purchased a 50'' 720p Plasma for the basement, "media room". The easy pick would be a Blu Ray player for this unit, but is the difference worth the additional $100-200. Am I missing out on a noticeable picture difference if I go with another top of the line up-convert, assuming I'm not interested in building an expensive Blu Ray disk collection?

In another forum, the advancement in sound quality was brought up. My counter-point was that I am running a Panasonic receiver and speakers from 2000, which only has a DTS chip. I wouldn't think that the newer Blu-Ray sound technology would translate any better when going through my current receiver.