I used to play inverted but for some reason I can't anymore...
I have low sensitivity which doesn't suit my playstyle well (rambo) but I don't have the patience nor the skill for the other types.
I pwn with a BR in halo 3 though
PC: Mouse, these days WASD although I used arrow keys for far longer than most (I recall my first run through of Deus Ex was done in this manner) and my initial messing with WASD was with A and D set to turn. Never used numpad keys mind.
Sensitivity. We have multi DPI mice for a reason.
Rarely do I use a controller although my PS1 controller appeared for halo and jedi academy (guns were not such an important feature here), vehicle sections are a different matter.
Assuming I am lumbered with a pad.
Inversion: get out of my sight.
Sticks: move and strafe on one stick and aim on the other. Exception in some cases being for the N64, I can not abide forward and turn, strafe and up/down config.
Old style single dpad, not really tried it other than a brief spell of dark forces for the PS1 on an original controller (which may have not even been real, I recall it was one of the first games to use the dual shock) but that shoulder buttons if it was anything. First person on common 16 bit era consoles was practically unheard of outside of RPGs and rail shooters which do not count here.
Style. Depends on the game really. Regardless though I shoot to kill and aim to hit all targets with all shots. Suppressive fire and/or blanket cover is not something I go a bundle on.
Such a philosophy tends to also influence my weapons of choice and result it me sticking with a "sniper" rifle far beyond what might be considered wise.
Stealth: whoever is left standing once I loose rounds is either not a threat or he who kills me. I will pause for a good shot but doing the proper sniper routine is a sure fire recipe for boredom.
Teamwork. If I am in a good one then I will go in for it, I favour strategy over multiple person army though. In a bad one I will look out for me and then help if I can.
Rambo stylings: I will confess to a great like of recreating [insert scene from cheesy film of choice] with a shotgun/dual weapons on occasion although I like it more when I have others at my back cleaning up when it inevitably does not work out so well.
Always play inverted. Just seems normal to me - you tilt your head back to look up, and you tilt your head forward to look down. So mouse forward = down, mouse back = up. When I first started playing quake and having LANs with my mates from school everyone I knew used inverted, so maybe I just learned that way.