I've used an ETEN pda-phone that was supplied by work, I wouldn't even give that space in the bin

, If you are after a cheap wifi & GPS I'd recommend the Fujitsu N520 which I still own but no longer use, very smart & compact has a built in GPS receiver so no need to mess around with external devices ( only downside I found was that the GPS took a long time to lock on to a signal compared to the tomtom). I currently use a Dell X51v which has a very high res screen & is a joy to use apart from getting the damm thing to sync.
You seriously missed out in the trading section tonight, someone sold 2 Dell X51's for £80 the pair