@Waffle:
While I wouldn't ever say it's a waste of time, I certainly don't think it's a particular efficient use of time.
Sure, there'll be the occasional story like yours where study of an opening correlated with a big jump in rating, but that's pretty unusual.
At the level those questions about openings are usually asked, tactics should be everything. Knowing some opening lines well won't help if the player drops some material every few moves.
Now, having said that, as has already been pointed out in this thread, for a lot of players studying openings is more enjoyable than studying other facets of chess.
So, while it might not be the most efficient way to get better, that may not matter so much, if you find it a lot of fun [after all, having friends and drinking some good beer are terribly inefficient ways to get better at chess, but I'll do those anyway :)]
@IonParticles:
The best openings for you are the ones you enjoy. Sure, people can do some deep analysis of lines and conclude White has more of a pull in one line than another, or that Black's closer to equality in one variation than another, but that's not so important unless you're playing at an incredibly high level (think world elite, top engines, or correspondence).
Using online resources or books, survey a bunch of openings and find ones that you like playing.
Provided that the position you enjoy playing isn't just awful, you'll do better that way than trying to force yourself to play something you don't really enjoy.
I've used the analogy before, and I'll use it again. Openings and training regimes are like diets. Within reason they all work, and what matters the most is sticking with it.
The most efficient training program in the world won't do you much good if you quit after a week, while an inefficient one you enjoy could go a long way if you enjoy it and stick with it for years.
Find what you enjoy, and play that. 'Nuff said :)