bocamojo, thanks for your comments.
I understand you point of view on the Dell 2001FP and I certainly looked at that as a possibility. As a matter of fact, it looks like Dell UK have started discounting their LCDs again so a 2001FP would only cost £385.75 as of now.
However,
this article gave a fairly convincing argument for choosing an S-IPS panel as a good compromise between colour accuracy and response times (across the whole gamut of grey-to-grey transitions) and, on that basis, I have been looking for that type of panel for my friend's usage pattern. I have also been thinking that for games, a target resolution of 1280x1024 with lots of anti-aliasing etc. may be better than trying to shoot for 1600x1200 and I'm not too sure how the well the Dell would scale down its resolution.
Another thought has been that, should he choose to hang on to his Iiyama 19" CRT, the optimum dual-monitor configuration might be 2 lots of 1280x1024, as I don't think his Iiyama would handle 1600x1200 particularly well. At this point I just don't know whether he will opt to keep two monitors on his desk
Anyhow, it's certainly not an easy decision.
On the NEC DVD, I have read reports that the 3520 is relatively noisy compared with the older 3500 and the LG. Also cdrfreaks gave the LG an Editor's Choice award and it supports DVD-RAM, which could come in handy.
I agree with you about ATI for 2d quality having seen DVI compliance test results but I think that at 1280x1024, any problems in this area are not likely to make themselves visible. On balance, I went with nvidia for the not-so-compelling reasons of its Shader 3.0 support (have read about missing visuals in some games without it) and its relative Linux-friendliness.
On overclocking, I agree with all you say and intend to keep the voltage at stock or certainly no higher than 1.5V.
I am now panicking because I realise that I have chosen four IDE devices and yet I have only two IDE channels. I believe it is best to keep devices on separate channels because only one device can be active on any one channel at any one time. I'm hoping maybe I can run the optical drives off SATA with some kind of adapter, otherwise I will cancel the order for the Samsungs, even though they are the only quiet option at 200GB (SATA version unavailable as of now).