Mobipocket Pro is the best ebook reader. :P The office companion available for it can be very useful.
I have an ambicom compactflash bluetooth card and the dell 802.11b card for wifi. Both work fine.
I had bought Pocket Map Navigator from pocket map and I was constantly struggling with it. My mom got a new axim with the Navteq gps software, and, since she wasn't using it, I swiped it. That software is great! Way better in my opinion. I use it with a holux bluetooth receiver. Not sure but what I might have liked a sleeve better - the receiver slides around on the dash and can be a pain to pair up sometimes.
Divx has a conversion option to compress avi files for handheld devices - think it's $10-20 can't remember. Put those on a 2 gig cf card & I can play videos in the car using the core tcpmp media player from
www.tcpmp.com - piping the sound thru an fm tuner that plugs into the headset jack.
There's a browser program that helps make the internet a little more friendly, although not much. I've only tried PIEPlus - dunno if there are others out there or not.
I use a program called MemMaid to free space - especially browser cache, etc.
Oh, and Microsoft Money INCLUDES the pocket pc version - unlike Quicken where you have to buy the ppc software separate.
What else are you wanting to do with it?