oh, and also the Torchwood series, if those people feel left out.
For the ones who agree with the title ("Doctor who? ..Just Doctor? What?!"), get enlightened here:
It's a classical scifi series, took a break from the end of the eighties until 2005, and is currently on its third season since then.
Search around for clips on youtube if you'd like a look at the current series. It has already had two doctors, by now. The current actor is David Tennant, not that you're likely to know who he is if you're at this section.