I will attempt to stay on topic and respond to the thread starters questions.
The difference in palm and PPC is the operating system. Palm is its own OS while PPC is basically a scaled down version of Windows. The pocketpc is going to cost you more to start but its going to include a lot of things like word and excel that would cost you extra on the Palm. The PPC is more like a scaled down version of windows and the palm is a simpler operating system which is easier at the cost of features.
Typically your going to spend $400 for a decent PPC while a decent Palm is going to be around $200. The palm is generally going to be smaller and have longer battery life while the PPC has a bigger screen which makes them overall bigger and have shorter battery life.
As far as caching goes your going to need a map program and something to read GPX files. I love mapopolis on my PPC and as far as I can tell the palm version is similar. The only big complaint I've heard is how you get waypoints into the palm. They show up as contacts in your address book. For reading GPX files I use GPXsonar, its free and very easy. All I need to do is copy the gpx file to the PC I don't have to do any tweaking or converting. I'd bet there is something similar for the palm.
So it depends on what else you want to do with your pocket device. Is there a certain program or peice of hardware you want to use? Do you want a bigger screen or a smaller lighter device? Do you want a simpler operating system or one with more features?
Off topic alert
Jeremy can your palm do this?
-Terminal Server Client
-HP remote insight board client
-HP insight manager
-voice over IP phone
-browse network file shares
-Pocket RAR (unzip rar or zip)
-Virtual display (rotate, scroll, or compress your display)
-Play WMV, divx, vidx files (plus almost any video or audio file format out there)
-arcade and console emulators
This is not a list of everything the palm can't do, its a list of what I do on the PPC that I don't think the palm can do. I use my PPC for all these things.
Sorry for the slow reply,had a slight geographical relocation for my work...hehehe...closer to Boracay Island now....woohooo
Also,thanks for steering the topic back on track
To answer your question about what else i want to do with it....basically anything it lets me. What i mean by that is,the primary objective is to use it as a "caching tool", with minimum(or simple) steps to get the cache info onboard. Whatever the unit does outside of caching is simply a bonus.
As stated - money is no object