Asus have been in the WinMobile game since WM 2003 at least. I know this for a fact because 2 years ago I had a ASUS p505 which was running WM2003. I actually sold it to my stepdau..who promptly busted it within 6 months.. kids
I've never been a fan of the chopped-down smartphone variants, but would be totally lost without my WM6 pda. I use it to keep track of personal and work appts, contacts. The fact that it syncs with outlook for all this is invaluable for me. Winmobile 6 is ok, though not a huge step up from WM5, though it looks like MS is doing some major overhaulin for WM7.
WMDC(window mobile device center) on vista is great, a superior improvement over MS activesync(xp and earlier)
Might even be worth waiting for the WM7 generation phones negsun??
I have HTC touch, which I love the look and feel of. Whilst I manage ok for what I use it for, I recommend people get the dual core version, coz its quicker, and more effectively used as a mobile media device than the first gen version Ive got.
Easily the best site to keep track of all things WM and smartphone is 4winmobile
. As it's a UK site, all of the stuff about contracts and carriers they may mention will be relevant to you negsun(much less so to me!) I used to be a reg at their forums but only have time to lurk here nowdays