Erik,
The reason for your name in the private profile field is so I can respectfully address you. I like calling people by their name, I'm not divulging your entire or last name. My apologies.
I had a Treo 650, it did fine. There was one quirk if you had bluetooth enabled and then datebook displaying on the home page, or something to that effect. Other than that I never had a problem. Palm/Pocket PC devices are cheap, combining it with a cell phone is more expensive obviously. But to get a basic palm PDA to act as your portable computer should do the task just fine for you.
A browser will be required for use of a platform such as BlackBerry and iPhone. The only time you'll probably not have an Internet connection is when you're flying! Again, if this device is crucial to you, you know you have other options and I encourage you to use what makes you happy. We will do our best but native iPhone integration is probably not going to happen, but anything can change at any time depending on what developer tools become available. You will also have the option to use a 3rd party product such as
StyleTap to run Palm apps on an iPhone as another option.