I'd recommend getting an nVidia graphics card in case you want to go/try Linux - nVidia Linux drivers are currently way better than ATI's. This
Novatech 6200 256Mb card is under £50, or this
Novatech Geforce 6600 256Mb card for under £75.
A word of caution though - don't even consider the graphics card until you have decided on the PC you want. The above cards are AGP cards, your new PC might use PCI Express instead. Besides, if you are really not that fussed with games you could just go for a PC with fairly reasonable on-board graphics?
For the PC, I'd personally avoid brand names like Dell in case you need to replace/upgrade parts such as the motherboard , and go for a standard-parts cheap option
like these. However, there is no doubt Dell do good offers, so if you want a PC to just use and more or less throw away in a few years, look at them too.
