pocket pc for air navigation

I am about to take the plunge a possibly buy an etrex and PPC.

I plan to hook it up to a Pocket PC (I have neither at this point) and use
the PPC/etrex combo as an avation/flight plan/navigation multifunction
gadget

if I only wanted navigation and I had lots of money I would buy one of those
super-complex specialized aviation GPS ... but the pocket pc is expandable
and I can do other things, like flight planning, weight and balance,
checklists, that most common areonautical GPS don't come with and when they
do... they cost a kidney and and a leg.

I am not too concerned about technical challenges of connecting the two
togheter but I would like to know from the community, if anyone has tried an
Etrex/PPC combo for air navigation?

Which one would be the best to get? Etrex Vista? Legend? (since the etrex
would be used 90% of the time as an appendix to the air nav software running
on the PPC I wouldn't need to spend too much on it).

Anybody ever bought a used Etrex? Any bad experiences with it? Which PPC
would be the best to work with the etrex?

Are there any pitfalls I should look out for? Would I do better getting an
GPS expansion for the PPC instead of a completely separate unit?

Just feeling my ground before I start dishing out money.

My budget goes from 300-500 (would like to keep it under 500 bux if I can).

Any advice/comments are much appreciated!

--
Marco Rispoli - NJ, USA
I SOLOed!! You can read my flight training diary at
http://www.tranceweb.net