I had the chance to play a bit with Canon EOS XTi / 400D a few days ago, and as onwer of a Canon EOS 30D, I must admit I was very positively surprised.
If someone asked me “Should we get the Canon EOS XTi / 400D or the Canon EOS 30D?” just last week I would have directly answered the Canon EOS 30D but today I might have a different answer.
In two words the Canon EOS XTi / 400D is a great piece of hardware. Really amazing and its Image Quality is great too even at ISO 1600
1) I like it because it is small and light: I am not complaining about the weight of the Canon EOS 30D but if you like to travel light the xti is really great
2) I used to hate the Canon EOS 300D and Canon EOS XT / 350D just because it was so hard to change the settings, well this is not an issue anymore, I like how nice and easy it is to change settings and they are displayed on the big LCD, the missing top lcd is really not a problem. Of course it is still faster to change, at least for me, on my 30D because I’m used to it but the 400D is really good
3) it will save you money to buy better lenses
so if you are a newbie and never been spoiled by the Canon EOS 10D / 20D / 30D back wheel then my advice is really consider the Canon EOS 400D.