I'm probably biased on this too, but here's my suggestion.
Get the Zaurus. for a lot of reasons. Here's three quick ones.....
-built-in keyboard is more useful than you may initially think, especially for the Linux console.
-has both CF and SD slots. (wireless card + 256 MB of storage with no bulky expansion sled)
-it's VERY easy to flash the ROM for OS upgrades/changes (I recommend
Open Zaurus (OZ))
of course there are downsides to everything. the only real major one I find with the Z is battery life, especially when using a wireless card. However the battery is replacable, so buying a spare is not unreasonable.