Does anyone watch Dr. Who

Excuse my ignorance but I just got into this show like 2 weeks ago. Today I saw a part of a rerun back from 2008 with a totally different cast and better special effects. I just have one question: What the hell happened? From what I can tell the show used to have a better lead actor (who is not a dork like the current Dr. Who) and better special effects. WTF? Can somebody please enlighten me?