Smartphone: if you want an amazing phone with great Outlook intergration.
Pocket PC Phone Edition: if you want a Pocket PC. (with some phone stuff in there too)
I know the Pocket PC is fully /featured/ as a phone, it doesn't have the same feel as having a actual phone.
The Smartphone is much closer to the size of a normal phone, so it'll actually fit in your pants. Plus you can do it /all/ with one hand. (mail, games, web, anything!)
I have an MPx200 with Smartphone 2003 and I love it! I think you'll love a Smartphone too!