Ok, seeing as others have chimed in with their other 'older DSLR camera' input, here's mine.
I bought the Canon 350D (2nd 'entry level' Canon DSLR - aka 'Rebel XT' in some parts of the world) back in 2005. I had a few digital P&S cameras before that, and was deciding between a 20D and 350D.
The 350D was slightly newer, cheaper - but didn't have all the same features of the 20D (eg real dial, as many Custom Functions, etc). I decided on the 350D, mainly due to price and size. I was happy with it - and have taken many photos over the years (probably over 100k photos now).
In 2009 I bought the 7D... it was a definite step up for the 350D, and soon after the 7D had been announced I 'knew' this was the 'upgrade I was waiting for' (the 30D, 40D, didn't cut it for me). The 7D has been my workhorse since. The improved AF, handling, LiveView, higher ISO capabilties, bigger, brighter OVF and screen all really made the photographic experience more pleasurable. With my 7D I usually use my Canon 15-85mm USM IS lens.
Having said that, I still do use my 350D for the following:
- time lapse photography (either macro - with Canon 100mm USM macro or landscape usually with my Sigma 10-20mm), and my Hahnel Gigapro timer
- teaching friends / relatives aspects of DSLR photography (I give them the 350D to use / practice with often with the kit lens 18-55 attached)
- outings where I want the lightest / smallest travel package, again using 18-55 kit lens
- back up (eg when I have had my flash on my 7D serviced, under warrantee).
I hope to always keep my 350D as a backup, particularly as I have 3 well functioning batteries for it... (I have 2 for the 7D - which do last longer, but that's another story), and the 350D uses CF cards (win!) When I run my 350D photos through DxO Optics Pro, I do find I need to adjust the settings a bit more than I do with the 7D (ie for more saturation, sharpness) to get the same results that I'm looking for.