I got the HP Ipaq 5935 direct from HP for £268 inc postage.
It has an excellent GPS rx, and works great with Seeyou gliding software, and Fugawi UK OS maps, (once youve worked out which ports to use) Tom Tom europe is included. Battery is fine for an all day walk with the GPS on all the time. Also has Wifi, plus the usual gubbins. Currently my fave gadget.
Unusually for computer hardware, I think since I bought it, the price has gone up.
I tried a couple of non Windows programs, (eg the PDA Firefox) but frankly the windows work better. A downer with this device is that Skype doesn't work on it.