I like unorthodox openings to surprise my opponents.
your natural opening

The French defence! Not overtly tactical or theoretical but still lots of pressure on white's position.

Scotch opening. It releases central tension and gives white good chances. It occurs after making natural moves (e4, Nf3, d4)

As white - Ruy Lopez. It's supposed to be really complicated, but when someone plays a symmetrical e5 it usually seems to work out pretty well for me :P
As black - Robatsch Defense with d6 against queen pawn openings, because it's pretty flexible, or Old Sicilian (2...Nc3) against king pawn openings, because I like my knight to wear a pawn for a hat on correspondence chess.

yes, I also like the french (hence e6) and the scotch - you must like the sicilian set up as well!
unorthodox - KIA!

how about let's list openings for
White
Black
KIA, e4
najdorf, King's Indian defense, queen's indian defense

Usually I play the Four Knights Opening, Philidor Defence, Scotch Game, or some minor Sicilian variation. Those are the openings that are comfortable to play in fast games. In slower, OTB games I am a bit more flexible.
Very interesting.....as white, my natural openings are the Catalan, Kings Indian Attack, and Queen pawn games. As black, it is the French defence. As white, you will notice that they are not formulaic at all, and are thus very flexible...

For white I guess four knights is the most natural, I've played it a lot and I know the tricks.
For black I'd say Pirc. I like to play a more defensive style, while building up to a crushing attack. Pirc does that more often than not.

with white, i used to play c4, in my former years i ued to pla 4, but talking about my defenses , i always use an unregular one!!
I'll let you know when I figure it out. Right now as white I usually open with D4 expecting the Queen's Gambit, and as black I usually play Sicilian vs e4 and QGD vs d4. I might start experimenting though, not sure I like any of them really.

I prefer open/semi open, I'm not comfortable playing cramped or very positonal. I prefer tactics, which makes me a poor competitor for a computer but that's OK. At this point, I don't care about losing. I just appreciate the aesthetic nature of the game.

I'll let you know when I figure it out. Right now as white I usually open with D4 expecting the Queen's Gambit, and as black I usually play Sicilian vs e4 and QGD vs d4. I might start experimenting though, not sure I like any of them really.
try different variations of the sicilian - each lead to different playing styles.
as for white - e4 is naturally more exciting than d4
what do you consider to be your natural opening? By "natural" I mean that fits your style, that without reading books the moves just come to you by instinct.
While I like the King's Indian Attack and King's Indian Defense, I have learned these by observing bobby fischer and reading opening books.
I consider my natural opening to be a variation of the queen's indian defense -
with Nf6, e6, and b6, because it is logical and challenges the center with flank tactics.
What about you?