Kirk
Sort of nearly correct on the plasma front:
The TH-37PWD4BX is 'normally' supplied with the plug in RCA terminal board for Composite, S-Video and RGB or Component video.
The TH-42PWD4BX is 'normally' supplied with the BNC terminal board for Composite, S-Video and RGB or Component video and there is also an optional DVI board that can replace the BNC board.
The Toshiba 42PW16 (clone of the TH-42PW4B Silver Panasonic) is supplied with in-built Composite, S-Video and RGB or Component video sockets (RCA).
As per previous posts the best picture quality from your SKY box will be achieved using the
JS Technology RGB to VGA plasma interface - you can connect this into either the VGA port or the RGBHV terminals (you just need the correct cable); if you are planning on a Progressive Scan DVD player with Component out its best to wire the SKY box via the
JS Tech converter into the VGA 15 pin socket (assuming you don't want to have a PC in your system).
I would not bother with a ProV or any other external video processor (iScan etc) at this time - Panasonics in-built scan converter is very good and I would put the cash towards a better DVD player.
I'm not sure about Andrews RGB pass through on the SKY box for your VHS deck - unless your VHS can somehow output RGB it wont work (maybe I'm wrong here - someone with a similar system can confirm); normally I would expect to see a SCART connection between the VHS deck and the 'VCR' SCART on the SKY box to give you Composite recordings from SKY and then if your VCR has a second SCART or Video out this would be fed separately to the Composite in on the plasma.
I trust this all helps - a little.
Best regards
Joe