It'd be more like £50-£60 to get 2GB of RAM that matches what I've got; moving to 4GB of the kind of RAM which costs £30ish would be something of a sidestep and likely wouldn't help that much. I've got corsair XMS6400 800Mhz DDR2 at the moment, and at the time of buying that was one step below their uber high end Dominator sticks. That still seems to be the case; it's still being made and the timings etc are all still very high on the scale. That's how I've managed so well with 2GB; smaller and faster can beat larger and slower.

I can afford to do that. I won't be happy doing it unless there's a real difference; I'd prefer to spend the money on something else or save it for a rainy day if the difference is only going to be minor.

I've got an 8800 GTS, not the king of cards like it used to be but still more than capable of running most things at high settings. I feel that with Civ 5 and a few other forthcoming games I have some interest in it's my CPU and RAM that are beginning to hold things back. A bit of looking around shows that the E6600 is great for overclocking so I can probably boost that from 2.4 up to something like 2.8-3.0 without needing additional cooling etc.