I do. I have since the fall of 2007, when I first learned what the word was through my college LGBTQ group. Before that, I identified as bisexual but always knew that I would be open to dating people who were trans, not just cis-gendered people or anyone of any other form of gender identification and anyone of any orientation. None of that ever mattered to me as long as I connected with the person on a basic human level and was emotionally and physically attracted to them in some way, shape, or form. So discovering pansexuality was really a blessing because I was finally able to identify myself better.
I personally do identify as pansexual. However, pansexual is not a term that most people are familiar with. So, when I tell people about my orientation, I typically say that I am bisexual, rather than pansexual.
Technically, I would describe myself as pansexual but I feel weird identifying with it strongly. Labels can be really weird at times and sexuality can be fluid. Since I'm a man in a relationship with another man, if I just say I'm "half-gay" people get the idea without really fixating on which label I'm choosing or me having to explain pansexual to them if they don't know.