I've seen so so many times people slagging off Sony entry level DSLR's for the reasons that lenses are not widely available etc etc etc and thus a Canon or a Nikon would be better.
For one the whole thing is a contradiction.
If the OP is looking for an entry level DSLR for casual stuff - not "
ultra ultra serious with photography" as the OP as suggested then what's wrong with the Sony A200? It has more features than any of its competitors and lenses are available fairly cheaply - just look at all the posts on AVF of 2nd hand Minolta lenses....I bagged a Sigma 10/20mm and a Minolta 50mm f1.4 (nifty fifty) 2nd hand at descent prices.
It even comes with a kit lens which is OK for a casual user. Yes its not great but it is a lens which non of the competition include. Plus having Auto Focus and image stabilisation are plus points.
If your not going heavy into photography and are just a casual photographer who only does it as a hobby then Sony DSLR's are more than adequate.
Forget about the Canon/Nikon nonsense if your not thinking of taking up photography seriously. And don't worry about the availability of Lenses for Sony DSLR's as there are always plenty going 2nd hand on AVF at very good prices.
The money you save could go towards a tripod, filters etc etc
If you find that in 6 months you want to upgrade then move on up to the Sony A700 which is brilliant!
I use to have a A200. It was my first DSLR and I loved it. Learnt a lot from it and then moved up to its bigger brother. I managed to sell the A200 for what i paid for it so i lost nothing on it even though I had it for 6 months.
I know over here Sony DSLR's are not favoured but over at AVF they are highly sought.
D40 vs A200:
http://www.talkphotography.co.uk/forums/showthread.php?t=76788EDIT:
SONY A200
10.2 mp
18-70mm lens lit
SuperSteady Shot feature
DOP preview (with dedicated button)
Dust reduction mechanism
NIKON D40
6.1 mp
18-55mm lens kit
no DOP preview
no dust reduction mechanism
lack of focus motor in the D40X body - You need to buy a lens with the focus motor in the lens, so Nikon SWM (I think!!) Sigma HSM, and as far as I know, there's nothing by Tamron.
The D40X only has 3 focus area points, unlike the Sony's 9.
All shot with the kit lens on my A200: