In all honestly I would recommend the HP RX3115, I have had many pda's over the years and this one is by far the most amazing.
http://www.amazon.com/exec/obidos/tg...12902?v=glance
Provided you simply obtain the bluetooth version of tomtom, you can use it for it's GPS purpose then take it inside the house where it picks up a wireless signal before you know it. It's easier with how everything is built in so you're not having to buy bulky expansions and so on.
We used the wifi aspect of it alot when we were in Canada and the display (although small which is understable) is great surfing the internet and sending full emails with attachments. If you're smart, you can wrangle one for about £100 (exchange rate on your benefit) from the US.