First of all, stop using the word "so" at the beginning of your sentences. The current fad of starting every conversation with "so" is pointless and practically idiotic, and letting it slip into written English is nonsensical. And please don't point out that there are reasons to begin sentences with "so." Of course there are. If you have a legitimate reason, do it. Otherwise, don't.
Beyond that, in my opinion, the best opening lines are ones that simply put the reader into the middle of the action. Try this one on for size:
Charlie was thinking, Bennie, I told you no way a friggin' .22, because look at that,the creep was only bleeding, and running, getting away, and it didn't do Charlie no good to be right about the gun now, cuz how was he gonna tell Mr. Carter and come out of that alive?
Do you want to read the rest of that story? I hope to heck you do, because if you don't, I'd have to wonder if you have a pulse. You're looking at four characters, one of whom was just shot, two of whom are possibly friends and maybe rivals, a whole bunch of interaction that obviously has already happened among them, one guy who is probably going to kill another guy for not killing someone whom he wants killed... I could go on. There's a heck of a lot happening in a single sentence, isn't there?
Start your story in the middle, using an opening line that talks about something that is really interesting but doesn't reveal it all, then go into backstory, and usually your opening line will be plenty interesting enough.