It really is a simple equation. It has to be what you think looks good. As a start the most basic hairstyle for the bangs is the off centre part. Why? Because it works, it really does.
The other styles are
Completely pulled back: You don't see this one very much any more, it leaves a lot of forehead open so it's hard to pull off unless you really do have the face structure for it.
Straight bangs: all the way across. This one can be done VERY well, and if pulled off can be superior to the part ( I prefer that part but that's just me) but it does take once again a very specific length of bang and face to pull this off or it just looks like you forgot to do you hair that morning.
LIke the others been saying, it depends on your features but I think straight bangs are harder to pull of. I would think a guy would like to see more of your face, so side swept bangs.Just my opinion though.