I remember, back in the day, buying a 2mp Minolta camera, and just how disappointed I was trying to get it to take a decent photo. So, since then I've not been that enthusiastic about digital cameras/SLRs. Until I bought the 400D. What an amazing camera! It's everything I always wanted in a camera (although I'm relative newcomer to photography).
It does everything I could possibly expect from a camera and there may be a reason why you would want to buy a more expensive than this one, but I honestly cannot see why you would want to!
It's so quick at everything. Which is what you need when you really urgently need to take a photo. It takes less than a second to boot-up, the focusing speed is usually phenomenally fast, and it can continuously shoot 3fps for about twenty seconds. The menu system is great, and all controls are sensibly laid out. The camera feels rock-solid. It's quite weighty, so it may not be so good for people of slight frame, but it's a small complaint for such as awesome peice of kit. The built-in flash is powerful (more than enough to annoy and blind my brother) and even on the auto settings you get great daylight shots that require very little, if any, touch-up in Photoshop. I would say buy a decent lens, because the 75-300 Canon lens I bought suffers from a bit of blur, and chromatic abberation, especially on full zoom (that blue tinge you see around high contrast subjects). You can sort these things out in Photoshop, but really you'd be better of buying a decent lens to avoid these problems in the first place.
The battery life is excellent, and you can pick up cheap replacements or spares.
I'm not sure whether the sensor cleaning thing works, but I assume it does beause all my shots have been noise free.
I love the fact that you can leave the shutter open for as long as you want. That's great for night time shots where there is little light, or when you want to do a bit of Astrophotography. I got some fantastic photos of the Orion constellation, and of a huge halo around the moon. Although I would recommend a tripod and definitely recommend buying a remote control so that you can take shots without the camera shake from pressing the button.
Well, for the last five minutes I've been enthusing about the 400D, but I think it really is that good. Believe all the reviews you see here and elsewhere. It is an amazing camera for the price.