What?! People still reviewing the D30?!
Well I bought mine on eBay last year as an upgrade out of compact noise hell, and am still having huge fun with it. ISO400 and below and the images are fantastically smooth. Shoot RAW and a bit of tweaking with ACR turns in perfect colour and lovely detail. 3.2Mpx also means you can use RAW with small CF cards and minimal processing time in Photoshop.
For a six year old camera with two previous owners who probably caned it as hard as I currently am, mine still feels solid, reliable and unlikely to let me down anytime soon. No creaks or breakages, and the cosmetic appearance is still great; testament to high quality materials. People have mentioned that the sensor res makes it forgiving to poorer quality lenses: maybe so, but I found that a 17-40L gave immediately noticeable and much nicer results than the cheapie Sigma 18-50 f3.5-5.6—sharper and much more contrasty.
I hardly ever use the built-on flash due to poor metering control, or any flash for that matter. A 50mm f1.8, ISO800/1600 and a judicious use of Neat Image have filled the bill for all the low-light stuff I've done (not to mention that flash is impossible or offensive to use in most places like pubs or theatres anyway).
As the cheapest way into DSLR and serious quality shots, a secondhand D30 takes some beating. Just remember it's an older Canon so will not use EF-S lenses.