I agree with Xtremegene...in regards to ActiveSync, having the latest version does not mean you have the best version. IMHO, ActiveSync 3.8 is the best version of ActiveSync for windows mobile 2003 (and earlier) devices because this version was very stable and you can still sync via wifi connection. There is no reason to "upgrade" to any version of AS 4.x unless you have a compelling reason to do so (another pocket pc that runs WM5.0 or WM6.x).
But, if the computer that you wish to sync to runs Vista, then you will need to use
Windows Mobile Device Center 6.1 to sync your pocket pc.