Radeon HD 4870 or GeForce 9800GTX+ ??????????
open to other ideas with reason.
spending around the £130-150 mark
Get Radeon HD 4870.
GeForce 9800 series uses the same architecture and the same G92 core as the old GeForce 8800 series so I would not consider them to be a new next generation GPU. Geforce 9800 should have been called as Geforce 8900 series. Basically, They are just simply overclocked Geforce 8800s with higher clock speeds but they were not meant to compete with Radeon HD 4800 series except for GeForce GTX 200 series which uses GT200 core and architecture.
However, Geforce 9800 GTX+ has 55nm GPU core but it is still G92 core which had been die shrinked to 55nm size.