I have discovered a very comfortable, flattering pair of pants: the Perfect Fit Pants from LL Bean.
My sister-in-law wears these, but is much skinnier than I am. I have a...uh...more womanly figure. (Read: extra junk in the trunk.) I avoid knit pants because they tend to ignore my proper butt and instead hug my under-butt, that pesky region around the tops of my thighs. The Perfect Fit Pants don't do that, so I highly recommend them to any of you ladies with under-butt issues.
They come in tall sizes, too!