What do I use a PDA/phone for?

Different people use a PDA and phone for different things. Everyone has different needs. This is especially important when trying to find the right device. I've been trying to settle on the right device for awhile now. About 5 weeks ago I finally decided I wanted a converged device. I knew there would be tradeoffs, and nothing would be perfect. I tried the Verizon XV6700, and it didn't do it. I've been using the Treo 700W for about a month now, and I'm finding it to have some issues. I can't help but wonder now whether the Treo 700P might be the device I'm really looking for. To that end, what do I use my PDA/phone for? Maybe this will help me decide which device is the right one for me.

1) Make and receive phone calls.

This seems obvious, but it's quite important. The device needs to do this and do it well. There should be no confusion or frustration.

2) Text messaging

Just moving to any PDA phone makes this better than on a dedicated phone.

3) PIM apps

I'm not really a power PIM user. I don't need all the fancy features in Outlook or some 3rd party PIM replacements. I just need it to work simply and fast. Short notes, calendar with categories, contacts, and tasks with categories. I LOVE the Palm OS PIM apps. Maybe it's just because I used them for a number of years, maybe it's because they are better for my needs. The Treo 700W is driving me nuts in this regard. The Pocket Outlook apps aren't enough; Pocket Informant is too much. It's just not simple and quick.

4) Bible software/note taking

Multitasking would be good here, but the limited memory on the 700W makes this an issue. Could probably just switch apps faster on the 700P. Who knows.

5) GPS navigation

This is big. I plan to use TomTom for naviation and talk on the phone simultaneously. The 700W handles this very well. Not so sure about the 700P after a bit of online research. If it can't, then it's not the device for me.

6) Email/internet

I don't need this a lot, but I do use it some. I'm finding that I use email on the PDA a lot more now that I have a converged device. It's kinda nice. This whole category would mostly apply when travelling.

7) Streaming audio

Again, only on occasion, but it should be able to do this.

8) Tethering

Only on occasion, but need the capability sometimes.

I just want the device that does these things and does them well. I want simplicity and ease of use. I want it all to just work w/o having to worry about it failing all the time. So at this point it's either the 700W or the 700P. But which one?