Not sure what happened to my last post. Meh.
Like Kazza said bear in mind you're basically buying into an upgrade route as lenses and many other upgrades are manufacturer specific. You certainly won't go wrong with Canon, Nikon being the other major player currently.
I have a 400D and love it, though it has been superceded by the 450D which has extra features like Live View (see what you're shooting on the LCD), 20% higher resolution (ish), Digic III processor (faster capture, higher quality noise reduction), larger LCD and better basic 18-55 kit lens (same lens, only improved). You can get a 450D + 18-55 & 55-200 zoom for around £675. I'd go for that if your budget allows. The 400D is not so easy to find any more at reputable dealers now it's been superceded.
I wouldn't get a DSLR wqith just a zoom lens though, it will frustrate you for those medium to short range moments, and the basic 18-55 kit lenses are cheap and good in anything other than low light.
An interesting example of 400D vs 450D pricing
450D with 18-55 & 55-250 £ 674
http://www.warehouseexpress.com/product ... ku=1025953400D with 18-55 £389
http://www.amazon.co.uk/Canon-Digital-C ... B000IKVOE8Plus 55-250 £193 (total £582)
http://www.warehouseexpress.com/product ... ku=1021795For the extra £90 I'd get the 450D