Everyone,
Once and for all, the Nimrod MRA4, is not a "brand new aircraft", at least not in the way you mean....
Yes, it is "new metal", and yes, it is a "new" design, i.e not just a re-worked MR2. However, the design of the MRA4 was 'frozen' many years ago, probably at least 10 years ago. The design was 'frozen' before bomb bay extinguishers and fuel tank protection were considered issues. Yes, no doubt they could be added - and I'm not saying they shouldn't - but don't assume just because the aircraft are only being built now that they are in any way state of the art!
The design for Typhoon was frozen in the early 90s, F-22 probably at least 10 years ago. There is one school of thought that says by the time any complicated military aircraft enters service these days, given the time taken for the programme (JSF anyone?), it is already obsolete!