Slacks are the worst, as the material isn't as tough and instead of just over hugging your nads, there's a good chance your ass will be hanging out by the end of the day.
A good rule of thumb is if it says modern or classical fit, stay away from it.
Levi's are great, and I'll second the 569s.
I also have a pair of shrink to fit 501s that fit great, but they are a bit tighter, but don't overtly hug my nads and the girls seem to like them better. I can't carry a bunch of crap in my pockets though.