The first situation is called a gutshot draw. It simply isn’t worth very much because you need an exact card to fill your strait. I wouldn't pay more than a minimum bet for a gutshot. If there are several callers to a baby raise then you may think about calling it, but if he raises anything like a pot-sized raise then you need to drop it. Straits are better in a way because they are harder to see than a flush. The problem is that if there are several callers and you make your strait the flush draw may make his flush and you’re out of luck.

First of all, if you have AA you want to try and raise enough so that you get one or two callers and force out the small pairs. Then if the flop isn't coordinated you want to bet about pot-sized. Beware of resistance at this point especially if there is no flush draw on the board. Someone with a pocket pair may have made set. You can bet a little smaller than pot-sized this time and still take away his odds. If you have bet at him on both the flop and the turn and he has called both I think I would check the river unless he is a fish. He may be slow-playing you.