Does it pay to buy a good video upscaler in my setup?

To convert 1080i cable hd tv to 1080p on a 50in 1080p plasma tv i'm sitting 13ft from?

If not, then when are the benifits of a good video scaler worth the cost as a rule of thumb?

1080i is not scaled to 1080p; it is deinterlaced to it.

Is your display not doing a good job of deinterlacing the 1080i signal?

my display is doing a good job, i was just curious to know is there a big difference between a 1080p dispay Panasonic and a good seperate video scaler. Are the differences small?

I've never seen a seperate video scaler in action

My advice would be to read the Panasonic threads in the plasma forums to see how well your particular model deinterlaces 1080i as I have not owned one personally.

Again though, what you are looking for is its deinterlacing ability, not its scaling ability if you are concerned about 1080i performance. Scaling is making the signal fit the display (say 1080i signal to a 768p display). Deinterlacing is converting the signal to a progressive one (1080i to 1080p).

Does your display accept 1080p/60 input? If not, the question is moot.

Good luck.:)