Help selecting GPS system

I need some help selecting a satnav system, preferable TomTom based. I want to spend as little as possible on this kit. These are the options -

1. I have an old Compaq 3630 which I could use. I suppose i will have to buy the software and a wired GPS receiver. Is that 3630 capable of delivering reasonable performance while calculating routes or rerouting?

2. Buy a Nokia 6600 or Orange SPV200E (very cheap for me on a corporate Orange deal), TomTom software and Bluetooth receiver. The downside I see with this is that the display is quite small and might turn out to be a bit ineffective. I have also read that TomTom supply the software preinstalled on a card, which will mean that I have no backup on a CD should the card fail for any reason.

3. Buy a new PDA + GPS bundle. The cheapest reasonable option is the Mitac Mio 168 + software. Alternatively it will be a HP handheld.

4. Buy a dedicated GPS system like TomTom Go. This si my least preferred option.

Options 1 and 2 in my opinions will work out cheapest. Any opinions/recommendations on this will be gratefully received.