Donny, the P-105 is a great choice if you don't need dedicated midi ports.
I went with the Yamaha P-95 as it has dedicated midi in/out ports and is not USB based.

It has basically the same action as the P-105.

I use the P-95 with the Tyros4 (mainly to play solo piano using T4's sounds) and to control some synth modules in my friend's studio.

Ron, the Casio PX-5S is high on my list for next year.

Ian