I've just picked up a brand new (still sealed in box) Tatum tablet PC (900mhz 20gig) with wireless network and a biometric finger print log in for £160 from ebay.
I can use a compact flash GPS (£20) for a GPS backup, but I usually just use the USB feed from my Garmin 296.
Both work very well with MemoryMap.
I do have difficulty looking at the screen in direct sunlight though, but apart form that It's a nice big moving map display for less than a couple of hundred quid.
And you can play solitaire whilst waiting for the weather to improve.
Rans,
www.FlightForLife.co.uk