Things I am done seeing as someone's profile picture on social networking websites and dating sites (not like I visit the second sort, but I remember those well enough):
Any amount of exposed flesh of a man. Put your shirt back on, this is not a flesh-bazaar. There are more than women on Facebook. (I almost typed fleshbook, God help me now that I put that out there it'll either be a website soon or is and I will now go make myself aware of it.) Even if someone waved a wand and all the men but you disappeared, not everyone would be interested in seeing you shirtless, and quite frankly... at least one of those ladies would be offended.
Money, people holding money next to their face/partially in front of their face/in their fist, cars (without the owner OR with a "model" on it), phones, guns, etc... in short POSSESSIONS OR CURRENCY. These do not make you cool, or convince anyone you are rich/successful... any idiot can go cash his paycheck and flash it for a pic. I am sure these things impress someone else, but I am not him.
People kissing. I am sure you love/are interested in them but... I want to see your face so I can see if I know you. Hard to do that when someone is busy trying to suck it off your skull.
People with multiple other people of the same gender. I realize you like your girlfriends. That's cool... so which person in that picture are you? Kinda want to know who I am adding, or who I am supposed to be considering adding.
People trying to look "hard," or express pain... pretty much anything but happiness, or of course a nice neutral look that does not seem sour. Look, I realize that you think you are gangster, or a thug, or feel so much internal pain that you cannot express it all but are trying as hard as you can, or perhaps when I look at your picture I am supposed to think you are artistic or neat. Neat, artistic things are, as my opinion goes, spontaneous. Never planned and controlled. Sure, you can plan to take a picture of tomorrow morning's sunrise, but Mother Nature may well flip you the bird and you'll wake up to clouds.
Children. Not pictures of your children, heavens no. Kids are great. Kids on Facebook, not so much. Used to be that you had to be 18 to have an account. Now it's 16, if I hear correctly. Logan will never know the myriad wonderful and hideous things Facebook can introduce you to until he is 18. Unless he does it behind my back of his own accord, then I will ground the holy hell out of him. Promise.
There are exceptions to every rule, but in general... save all of these pictures for your photo albums. When I look at your profile picture it had better say something genuine and honest about who you are, what you believe, or what you stand for. If you honestly stand for any of the things I mentioned... more power to you. Not to pick on any particular one too much, but if money is truly so important to you that you need to have it as part of your profile picture, grand. But I do not want to know you. Odds are that if money is that important to you... you are going to bitch like crazy when you don't have it. Further, it is no lie: more money more problems.
In short: be you, but be prepared not to be offended when I reject your friend request.