Not exactly original but close...
http://privateer.sourceforge.net/

Wing Commander I and Wing Commander II :)

Damn it, I played a great one (at least, I thought it was) when I was very young, and you actually had to refuel in-flight and do all sorts of complicated maneuvers, but I can't remember the name.
I guess Star Wars: Rogue Squadron 2 would be it. I sure had a lot of fun with that one. Wish I could say I've played those other popular Star Wars flight sims.

You can't go wrong with Freespace 2 :)

Microsoft Flight Simulator 98.

I would have to say Falcon 4.0, although the old school gamer in me is screaming out for me to say either Jet or Chuck Yeager Air Combat.

My favorite flight sim has to be the Xwing and Tiefighter series by lucasarts.

Falcon 4.0 was the first one I really got into, and it's still my favorite.

Wing Commander: Prophecy Never have i had more fun then playing that game, sadly i cant get it working on my PC now. Also entered on Facebook. No twitter, its so confusing and i have no idea how to use twitter. Yes i know im lame.

My favourite has to be IL-2 Sturmovik
Getting a friend to dogfight online with you with one of you flying and one manning the guns is just too much fun

Wingcommander Privateer, played that game to death

Wing Commander III: Heart of the Tiger; I loved the video footage between the flights!

X-Wing!

X-Wing is the best one :D

This will sound silly, but Microsoft Flight Simulator 5.0. My dad had it for our 386 back in the early 90's and I used to really enjoy flying around and looking at stuff :)