The PDA versions have lots of possibilities, but as you add functionality
...
I think these start at about $1400 if you get charts included.

AnywhereMap offers full solutions (PDA, card GPS, and software with
charts) for $899, along with some deal for continued chart subscription.
They offer both terrain and color, neither of which can be had in a
dedicated unit at that price. If I were going to upgrade I'd be hard
pressed not to go with them.

The new software inevitably requires things your existing hardware won't.

Score one for the dedicated units. My Garmin 195 is eight years old and
works gangbusters.

I am trying to wait for the new Garmin PDA due out this fall. I wanted the
tablet pc version, but for the money, I believe I will get a regular laptop
plus the Garmin PDA.

Sounds like a good solution, let us know how it goes.