I've always had the same smudgy eyeliner problem too.
I recently bought a Mac eyeliner gel and it is awesome. It comes in a little glass pot and you apply with a thin brush. It takes a little practice but now I find it easy.
Instead of my usual black I bought brown, which seems to be less ageing and more flattering (blue eyes, blonde hair).
I keep meaning to go on Facebook and leave a nice comment about the girl who helped me out at Mac, she was fantastic.