What eye liner color compliments dark brown eyes?
I go with anything too. The only thing I'd recommend is don't be matchy with the browns. I have almost black eyes, so I don't do deep dark browns except a bit to shade/define and go for coppers, taupes, and lighter browns. I think if you have light brown eyes you could do the opposite and use those deeper shades of brown instead of the lighter ones. I think the same is true of other eye colors too, like don't you think a dark emerald or forest green would look fantastic on someone with pale green eyes?
What some people miss, is that just doing black liner around brown eyes (like a "blackest black") can really bring out how brown the eyes are. My eyes aren't like "black brown", they're a pretty solid brown, so a trick i use is to put a DEEP subtle navy blue color in my water line, then do the rest of my makeup as usual and black eyeliner as usual. The blue is so deep unless you're looking closely no one will know you have on blue, but it will make your brown eyes pop! I do it all the time (:
The nice thing about having brown eyes is that you can pull off nearly every color of eyeliner. Mine are a honey brown (not super-light, but light enough that my pupils can be seen clearly against my irises), and I like to wear dark brown liner. I also like deep purple, navy, and deep green.