What PSP should I get?

I'm looking to get after seeing the new adverts on the TV and was just looking for a bit of advice on which unit I should buy. There's a new Gen 1 Base Unit for only �60 on Amazon.co.uk and I have seen the new PSP-3000 in the new argos catalogue for �136, is the difference so great that I should pay double for a device I will rarely use?