I was just about to buy a 2600 rather than shell out the £340 necessary to buy a set of toners from PC World, when I noticed that they are priced up and sold at £60 for colour and £50 for black. Way cheaper than staples online (£76 and £63 respectively), and almost makes it all affordable (almost).
The 'part' numbers are:
Still bloody expensive for nicely coloured dust, but thought I'd let people know in case their 2500 is about to become a doorstop. Remember, this is ecologically a LOT better than ditching the printer and buying a new one! HP even handle the recycling for you (prepaid label in the new pack.