I like the European (or is it German only) version. If you're a PhD, you're Dr. prof. XXXX, If you're an MD, you're Dr. med. XXXX.

As for me, I've heard that you get treated better with a Dr. in front of your name (especially by other physicians), so I would put it once I get the degree (especially, since I look like young and sketchy... it'll be a nice reaction to look for).