Love for me exists in the feelings I have for those I care for.
Other people have summed it up quite nicely, but I thought I'd add my input anyways.

Love to me is feeling that much affection for someone as a person I'd be liable to do almost anything for them. There's a distant barrier for me between like and love. I love my greatest friends and even more so than they, my girlfriend and would sacrifice a lot for them if I needed to. Those I merely liked, I'd help out if I could, but I'd be less likely to go to further lengths.

I believe love is something in my mind and thoughts, but it most certainly exists for me. And love doesn't have to be a two way thing either. You can love people who hate you, and hate people who love you.