Hi Someguy,
First off, if you're going to be selling your Vario II give me a shout, I might be interested in buying it off you. I'm waiting for the Kaiser to come out but would like a new toy to play with whilst I'm waiting.
You should be able to pop your existing sim card into a new phone providing the new phone isn't locked to a network. Regarding your new phone you've got a few options.
HTC have just released a phone with similar specs to the iPhone (i.e. touch screen, but no 3G) called the TOUCH. It is a windows media device but with a more user friendly front end for the phone stuff. Has had mixed reviews so I'd definitely see if you can get your hands on one in a shop first. It's available now, whereas the iPhone isn't
It doesn't really sound like the Ameo is for you as it's more like a PDA than a phone to me. Looks pretty clever but I've heard a lot of people say you need a bluetooth headset with you as you don't really want to be using it as a phone (due to it's size).
I believe Sony are meant to be releasing some new phones this week, so it might be worth keeping an eye on Pocket Lint as they tend to get mobile news fairly sharpish.