My first impressions of the SN41G2 is that it was not as quiet as I expected. However, after comparing it to my old PC and a couple of friends' PCs it is quieter and the "drone" is at a low enough frequency to fade into the background after a few minutes. It is relatively simple to replace the CPU fan with a quieter version and I guess part of the fun is to try and make the PC as silent as possible - at least that's what I want to do.
If you're on a budget, go for an Athlon processor based XPC. You'll get more bang for your buck and I haven't personally experienced any incompatibilities or stability problems that some hardcore Intel zealots like to go on about as a reason for not buying AMD. You can buy an Athlon XP 2200 for around Â£70 which is excellent value. Try http://www.pcindex.co.uk
to compare prices of UK suppliers for items such as disks, processors, video cards etc.
It's very easy to get drawn into the impression that you need to buy turbo charged kit at premium prices in order to use your PC. If you're on a budget then you can still build a kick-a*s PC without blowing the bank.