Hello to the op,
Well back in awhile ago, I had the same dilemma as you. To me its either the D40, D60, 1000D (Rebel XS, Kiss F), or 450D (XSi). I end up with the 1000D as I mentioned earlier. Here is why I chose it and not the others.
For this purpose I will only comment on the D40 and 1000D since their bigger/newer brother is about the same except with a few things better.
The 1000D like I mention has a lot of functions that will come useful to you as you get more interested into photography and by learning this functions earlier, it will help you understanding more advance bodies faster. Besides this what I like about the 1000D is that is has a dedicated ISO button, a jog dial which is useful when changing the aperture/shutter value. Things that I dont like is that it is very plasticky and the way Canon made their EF-S lenses like a no value lens (since its not compatible with Canon Full Frame bodies).
The D40 is my another choice, Nikon ergonomics is legendary (I used my friend D40x which is just a "upgrade" over the D40 and it feels really good in my hand), problem with the D40 is that its too basic and like some photographer told me, if you want to be serious in photography eventhough you are a beginner, ignore the D40/D60 and go for the D80/D90. Why did he tell me that? Cause honestly the D40/D60 is just too basic, you will quickly overgrown the camera and will want a better body to upgrade to since you are missing quite a lot. And I do consider the Nikon entry level bodies as the weakest in Nikon lineup cause there is no proper button to access to common use functions. But the D40 will of course still take excellent pictures. Now what the others are fighting over is the lack of build in autofocus motor in the D40/D40x/D60, but with Nikon introduction of AF-S lens, this wont be a problem anymore.
So I like the competition that both companies is having now, Nikon is certainly giving Canon a punch or two especially at the high end side, their D300 and D700 is AMAZING, whereas Canon is whacking Nikon on the lower end (450D and 50D - is certainly a superb camera bodies considering the pricepoint).
Okay now in terms of looks, I prefer Canon cleaner look (body and lens). I like how Canon lenses are designed, it looks clean and modern rather then the traditional look that Nikon has been using which I am quite impressed.
So in the end I end up with Canon thanks to its features which I have been using most of it.