Simon, memory is cheap enough that there's just no real good reason not to get at least 4GB. Yes, vista will run okay with 2GB but it will run much smoother with 4GB. As far as the timings, it does not really matter too much with an Intel processor, but technically 4-4-4-12 is faster than 5-5-5-15. So if you can get the lower timings that's great, but I'd not spend $20 more for them...it just doesn't make that much difference on an Intel based system. To state it simply, the CPU's large fast cache negates the need for super fast RAM.