I think I went a long time without really noticing one key person for the games I played. I don't think I noticed a celebrity developer before I started playing Guild Wars and followed the news on it, where Jeff Strain would pop up over and over. 

Lots of people have joined since of course.

The first? That's a tough one, but probably either Johna Carmack or Hideo Kojima. Nomura and Warren Spector are also possibilities.

Ken Levine.  Great writer with an incredible imagination.

For me, it's Kojima. You specifically requested developer, that's why Kojima takes the spot. My first video game related celebrities however, are Nobuo Uematsu and Yasunori Mitsuda. Musical composition gets my attention more that any other aspect in a video game, besides story.

Hironubu Sakaguchi followed closely by Hideo Kojima.

Mine was Richard Garriott, I suppose.

Brian Jobling of Zeppelin Games never missed one release by them on the C64, with Arnie 2 being the best.

Mine was Miyamoto

Pokemon - Satoshi Tajiri

The great Sid who stood the test of time.