The good thing about Windows Mobile is it's very customizable. You can hack the shit out of it and make it work the way you want to. Also, there's lots of customizations that make it way better than most phones.
I'm using an old 6700 atm, using ppckitchen.org to burn a custom ROM. My phone is 10x better than it ever was and I actually enjoy using it.
Also, check ppcgeeks.com they have a wealth of info for Windows Mobile programs/upgrades/hacks/roms.
(If you're GSM use xda-developers.com)
My 6700 with WinMo 6.1, HTC Streaming, Opera Mobile 9, Diamond keyboard (on screen), task managers and the a bunch of utilities, my phone can do just about anything.
I'm still looking to get the Diamond next week on Sprint though.
(More Rom, More Ram and More Power will make mobiling even more enjoyable)