I went through the same series of questions a couple of months ago.
I ended up with an O2 XDA Ignito (aka HTC Touch Diamond, but in a less tatty-looking housing). It does everything it said it would.
I had to work out a few bits to get it to play Modem to the laptop, but I can now do that via Bluetooth or via the USB synch/charge cable.
It also runs Excel and a few other packages that the iPhone won't.
All in all - very happy with it.
There are a couple of threads in here on the subject.