There are more obvious questions ! (Score 4, Interesting)

The simple fact that one of the biggest differences is made by having a multi-core processor when running modern Operating systems rather than raw processor speed should yield one obvious comment:

The cheapest Dual-Core processors I can quickly find :

• Intel Core 2 Duo E4500 S775 2.2GHz 2mb Cache 800FSB: £77.99
• AMD Athlon 64 X2 4200 AM2 2.2GHz: £45.04

The performance is within a hairs breadth of each other... and yes, when coupled with a modest graphics card they both do just fine in all but the latest bleeding-edge 3D games.

In other words, for normal home or business computing with light to moderate gaming - there is an obvious choice. Even with more demanding gaming, thats £30 more to throw at your graphics card which will make far more difference - or £30 more memory (2 GB !!!).

With this sort of thing going for them, and the higher-end really matching Intel in the price/performance stakes I suspect theres life there yet... quite a bit of it.

As far as graphics goes, everyone is happy to compare ATI with nVidia - but the only choice when it comes to on-chip graphics is not "ATI v nVidia" but "ATI v Intel"... you have looked at Intel graphics lately right ?