Re: MSPaint equivalent?
There isn't really an explicit separate program bundled, basic image editors are more hidden in other things like Preview and iPhoto (I think Keystone also has a few mods).
I installed Pixelmator. Not only does that have quite good editing resources, it also has a (somewhat too well hidden) vector mode. It's a good example of Mac software that beats the bejeezus out of far more expensive packages (and it's able to handle some Photoshop resources).
If you occasionally need to go beyond the basics but don't really need full blown Photoshop I'd recommend Pixelmator - also because you can properly try before you buy. It's IMHO worth the money.
If you want it free I concur with another commentard: Seashore will do you fine. I just stopped using it after I installed the above :).
Biting the hand that feeds IT
