For the true Dell price comparison
As said above at least compare Apples with Apples:
The monitor is not the same resolution, 1280 x 800 is quite different to 1680 x 1050, sure you can increase to the 22" with that res but we're talking a pretty naff monitor here, in my experience the Dell UltraSharp probably do just pip the Apple monitors for colour depth, but they're not an option. Assuming we're happy with the 22" to get the same res, add £30
Multimedia keyboard, add £5
No built in speakers on the Dell, not important to me, but are to someone. £10
Optical Audio output on the Dell? £10 as it's maybe included in the Audigy?
Webcam - £13
Wireless Network - £10
Bluetooth - £20
Firewire - £10
You currently get £60 against a printer from Apple too, so we can add a reasonable printer to the Dell (seen as you can have an HP C4180 for £60, effectively making it free) £40
That little lot comes in at £749.08, which yep it's still cheaper than the iMac.. but then we can talk about built in iLife amongst others, the fact that we don't have to install our webcam, plug everything in and let's be honest it's gonna look a whole lot better in the iMac form.... if you want to remove promo offers too, forego the printer which takes the Mac to the same £799 but the Dell now comes in £789.
I'd rather have a newer, slightly slower processor (seen as the OS will do far better with anyway) and the smaller HDD for the rest of the spec to be nigh on identical.... i get OS X you get an entry level Dell.
But as i said before, take your choice, i'll take mine... but if you're going to draw comparisons, at least make them fair.