will it blend?
You could just try and get windows mobile 6 and see if it works out for you. If it does you will be open to substantially more programs then WM2003. I think there is a version of opera mini for windows mobile which will give you a better web experience than with the aging version of IE that comes on it. Most windows mobile devices now days are smartphones there isn't much of a pocket pc/pda market now so that may hinder what you can run somewhat since programs may require access to phone functionality. Google is your best friend for finding out more though