Once again....
Derren has a point.
I also think dragons should have spellcasting, but I realize I think I use this a bit differently.
First; having dragons living in caves is boring. I liked having some dragons living in clouds, etc (silver dragons). TO do this, they need specific abilities and probably spells. I created custom spells for them, that are natural magical abilities. In my cosmology, magic is teh essence of the universe. Think of it, like the 'great serpent' hinted at in 2E now and then, and sometimes compared to asmodeus, lady of paint, elder breathren...all that jazzz. i just took my own spin on that stuff.
Anyways, books like draconomicon 2e, 3e and cult of the dragon 2e, have tons of dragon only spells. I think dragon should have, as derren pointed out, funtioality spells that help them accomplish their own goals, but it makes more sense after that, to have spells that they would create that make sense for them. Death Matrix is my favourite one and I can gaurantee, any high level party engaging a great wyrm in my campaign better be ready for something like this..via research, looking for signs of 'somethign amiss', etc.

Ain't revenge great?
Back in 2E, they explained more of ecology and personality, etc. As the style of the game has gone more towards hack 'n slash (really, that is where you need most of the rules anyways to be fair), there was less need for this; and thus now, at the tail end of it; they get rid of any semblence of "a grand holistic" view on specific creatures and instead just make them cannon fodder.
Also, Derren - we've alwasy been buying D&D books that don't have all the rules we want, and many players make house rules for it. It's how it is; nothing we can really do about that. They can't make a game that appeals to everyone 100%. I think 50 to 60% is good enuff
Sanjay