wodmarach: having finished the Space quest games (thanks to a kindly gogite) It's time to look at these since it's another series I've never played so which to start with people?
I haven't played the first two (a little before my time), but to be honest, it doesn't REALLY matter where you start. There is an overarching setting keeping all three together, but it's not really relevant. There are many recurring characters, but it doesn't really matter.
Pandora Directive is definitely the best in the series. A masterpiece.
While UAKM and Overseer are both brilliant, I find the former a bit too campy and I don't overly enjoy some of the puzzles in the latter. They are still solid 4.5/5 titles though.
I'd say that it's entirely up to you, but would probably nudge you to start with the dessert (Pandora Directive).
edit: oh and Overseer is a rehash of Mean Streets.