Hi Harold, welcome to the Cameralabs forums!
First things first: you’re right to consider a DSLR for shooting fast-moving subjects like kids. It can be quite infuriating to miss the moment with a compact.
Secondly, I wouldn’t be overly concerned about the lack of spot metering on the 400D. Its multi-pattern metering gets it right almost every time and you need only tweak the exposure compensation if it doesn’t.
As for the Canon 400D versus the Nikon D80, it’s really something you’ll need to weigh up for yourself. The D80 is certainly the superior camera, but it’s pricier and you may not need its extra features. Definitely pick them both up in person to see what you think, but if you end up going for the 400D, do consider upgrading its kit lens as this is the weak point in the system. A better lens should also focus faster, which would be useful for those fast-moving kids!
I’m sure you’ve done this already, but do read through the reviews of each camera, along with our 10 megapixel group test – the links are here:
http://www.cameralabs.com/features/10Me ... DSLR_test/
And we have a Canon kit lens upgrade feature here:
http://www.cameralabs.com/features/Cano ... s_upgrade/
If you’re after a budget DSLR, you should also be considering the Nikon D40 – see our review here:
Crikey, all these Nikon recommendations in a Canon forum. If this were another site, I’d be lynched!
Speaking of the forum, your question is one which has been asked and debated several times before, so check out what other people have been saying about both models - there's several threads in the Nikon and Sony forums.
If you’re weighing up the Nikon D40, D80 and the Canon 400D though, you’ll end up with a wonderful camera – all three are really good and you’re unlikely to be disappointed.