You want to get one of the high-end JVC models: HR-S7800 or above. They don't necessarily have a better tuner than other good VCRs, but they have by far the best tape playback. They're the only units below pro prices that include a digital time base corector. Possibly more important for your use, because they are SVHS decks you can get S-video out to your plasma when you use it as a tuner.
I tried a number of VCRs with my Panny plasma, and the JVC 7900 beat them all by a BIG visible margin.
I have the same exact model as you.It was absolutely hands down the best svhs vcr I have ever used.This is coming from a guy who literally auditioned ever svhs (jvc,tosiba,phillips,panasonic)vcr ever made.Best picture,cleanest signal.
My wife uses it to tune cable(with, for cable,very nice results)I usually only watch directv or dish or replaytv..
I am using a General Instrument DCT-2000 cable converter box which has both RF out and separate video and single audio outputs. This is going to a TIVO with S-video out, to my Panny plasma. I am currently using an RF cable between the G.I. box and Tivo. The TV signal on the plasma is pretty pathetic. Will I see any discernable difference if I use the separate A/V output instead of RF? Cablevision in my area doesn't have any more advanced equipment available.(in addition to not broadcasting the Yankee games)