Remember Pamela Anderson in the 90s? Always a brown lip liner with nude lips...
Please don't do this (again)!
But a darker red might work very well. Also I've seen already pink lip liner paired with bright red lip stick. Well blended this gives something amazing 3D to your lips! Or vice-versa: red liner with pink lips!
Try it out and don't forget to blend it!
all pics via http://maccosmetics.tumblr.com