Thanks for the info, it might persuade me to get the internal version actually.
As for the fan, I suppose it's there for a reason so I wouldn't want to remove it completely. It can be replaced easily if you lift the PSU out of the case. I wonder whether a slightly slimmer fan might cause less noise since it would leave a little gap between it and the grill in the case.
Aren't the quiet fans just operating at slower speed than the noisy ones? Then I believe a resistor on the fan cable might give the same result. I already did this in a Mac LC475 which brought down the noise considerably. It also has a CF card reader so sitting under the desk it's practically noiseless to me.