Here is the list of Software I use on my Ipaq 4705.
vxUtil
Spb Pocket Plus
Magic Buttons
The Core Pocket Media Player (TCPMP)
iSilo
Cash Organizer w/Money Sync
Pocket Informant
Pocket Profiler
WifiFoFum 2
Tweaks2k2


I know this isn't a smartphone and WM5.0 hasn't been released for it yet, but each of these programs list WM5.0 support.