No mention of the image sensor cleaner!?
I've had my 400D now since aroundabouts mid 2007, and I'm very impressed. I had originally bought the 350D, but I kept complaining to Jessops about dust marks on the image sensor. After repeated attempts at getting a decent 350D without marks on the sensor out of the box, I finally opted for the 400D upgrade.
They even price matched it with WarehouseExpress website pricing and I paid only £20 more for it over the 350D!!
The 400D comes with this image sensor cleaner, and it most certainly makes a vast difference! the 350Ds I owned kept getting dark blotches on the images, the 400 shakes the bigguns free every time! Its not perfect, some blotches are still there, but is well worthwhile.
I'm surprised this particular feature wasn't mentioned in your review.
Also the 350D used to appear to the installed software as a mass storage device to the CF card, this is no longer the case. Whilst this can be a major pain for downloading images off the camera for the 400D as you are forced into using their rather slow image transfer software, you can bypass all this by ejecting the card and putting it into a CF card reader on the PC.
Other than that the included software is very powerful, and can glean great unseen detail from the RAW format.
I opted to shell out for a 75-200mm sigma lens, and an 17-80 something Canon lens, both cheap-arsed but reasonable.
In time I want to get an image stabilisor and/or high quality Canon optics lens with deep telephoto. These are surprising expensive, but very very good, so look at adding a grand to the package for deep telephoto and good optics, or aroundabouts £500 for 'good' optics at medium range.
The same, though, can be said of the Nikon range.
One real annoyance is the screen on-off sensor, its the little gadget that switches the back-screen on and off depending on whether your eyes are up to the viewfinder. A good idea in theory, bad idea in practise, just imagine how much of a total pain it is switching on and off a bright display right under your eyeball during night shots - I've been slowly perfecting the art of moon shots for a while now. The sensor just doesnt work well in such circumstances.
A good camera in my opinion though - but will somebody explain to me why I keep having pangs of jealousy towards Nikon D80 owners!? ;-) As far as I can work out they're much of a much-ness except maybe for this unimportant auto-ISO thing.