Must be said, that the camera shop I worked at briefly this year were still using a 350D to take passport photos. Simple and reliable.

I bought a second hand 350D with 18-55m so lets see how it turns out.

thought you already had a DSLR years ago?

If it doesn't work out then Canon has an e-bay shop where they sell refurbished models - I got a Rebel xti from there a few years ago (which I believe is the Canon US equivalent of the 400D).

One issue with the tamron, unless they've updated it, is that the autofocus motor in it is really noisey. A shame as it is a really sharp lens, pretty good in low light, but typically when shooting in low light you're indoors and possibly trying to take photos in a quiet environment. It was noisey enough that I wouldn't consider using it unless I was at a very loud non-acoustic gig!

get yourself one of these:

http://www.amazon.co.uk/Canon-EF-50-1-8-Lens/dp/B00005K47X

A lot of Canon cameras of this age use compact flash, the in camera interface for the memory was never designed properly for the intense use it gets in a camera. Due to this the pins can break or bend and require costly repair. Other than that there should be few problems, provided you have checked the camera out properly.

I've got a Sigma 12mm-24mm which I've had a while but I find the images to be a bit blurry.
http://www.wexphotographic.com/buy-sigma-12-24mm-f4-5-5-6-ii-dg-hsm-canon-fit/p1524169

I have the Tamron 10-24mm, a comparable option. I was expecting minimal use from it but it's almost permanently on my camera. No blurry pics. If yours is producing blurry images then it's worth getting it checked.