You've certainly gotten an earfull on this Post. I really don't have much to add. (Thanks much, Wick, for subbing for me, et al.) It sounds like you decided. Like most of the FOllow-uppers have said, prep is the key. I'm repainting the interior of my house these days. I have 1 more room, the living room, to do. I've put in a boat-load of screws where the nails are popping out and then pounding the nails all the way through to my neighbors house. (Just kidding.) The nail-pops are just annoying when the sunlight hits them right. The wet-sponge trick is a good one. I'm no pro but I DO know that 2 coats of primer/sealer on new spackle is worth it. One just doesn't seem to do the trick. (I'm using Finneran & Haley primer, and paint.) This is another 'prep' tip for you.
As everyone elludes, the painting part is the easy part. Have fun. My best to ya and hope this helps.
PS: Sorry for the delay. Even though everyone else is doing their DIY jobs on the weekends, I take off from the Forum. Why? Because, well, I'm one of those DIYers trying to get something done too ... ;-)