Hard to say Stephen. I made my decision somewhat blind, in so much that I haven't tried the PA800 yet. I spoke to the Korg rep a few days ago, and I hope to have one in store early next year.
The demonstrations and user reviews of the Tyros2 were fantastic. I tried it myself, and found it to be a wonderful keyboard. I moved away from arrangers about 10 years ago due to the quality of sound available on the synth workstations, but I now feel that the quality of arrangers has made this fact redundant.
I have never been interested in synthesis, just powerful sounds, and I feel that the Tyros 2 is up there with the best available in the Synth market. And of course it gives me the chance to sit down and just jam, or use it as a pre production tool if I get a new song idea in my head.
The PA800 is supposedly a fantastic keyboard too, and a bit cheaper. But I wanted a new keyboard for Christmas (still a big kid!!), and was able to get a good price for the Tyros 2.
I don't think you will go wrong regardless of what choice you make across the board at the minute (including the E80), but I just think the Tyros 2 has that something special, and it also will look fantastic at home.
Good luck with your choice.