First, we need to make sure we're using the correct vocabulary and everyone understands what everyone is talking about.
Hypothesis: a tentative assumption made in order to draw out and test its logical or empirical consequences
Theory: a working hypothesis that is considered probable based on experimental evidence or factual or conceptual analysis and is accepted as a basis for experimentation
In everyday conversation, we tend to use theory to indicate an idea, or a passing thought, or how a certain thing should work (but likely may not work since we aren't working in a perfectly spherical vacuum). This isn't necessarily an incorrect usage of the word, but we need to remember that when discussing things in a scientific context, the above definition is the one to apply.
You all should have learned this in, like, 8th grade science. A hypothesis is what you start out with in an experiment. "I think thing A works like this." You then do experiments to test that hypothesis. If your hypothesis was correct, and you and a few other people do similar experiments and you all come up with similar enough results, then and only then do you have a theory. The Theory of Thing A. Or maybe [Your Name]'s Theory of Thing A. I mean, Einstein got to have his own theory; why shouldn't you?
We have Theories for all sorts of things. I'm sure you all learned about the Pythagorean theorem in your geometry classes. There are theories relating to pretty much every branch of science and math, and all using that same definition: a hypothesis with proof to substantiate it.
So when people talk about the Theory of Evolution, or the Big Bang Theory (not the TV show), those are hypotheses that have the support of evidence behind them. They aren't hare-brained fever dreams or wild speculation, but ideas regarding the nature of the universe that have been supported by the evidence found.
It seems like much of the religious science-bashers keep thinking of this word "theory" in the wrong terms, and it is supremely frustrating for those who separate their faith from facts. I know plenty of people of faith who wouldn't for one second try to argue the validity of the Theory of Evolution because they've read up on the history of the science behind it (it's not a new idea, kids). But they don't see the science as a threat to their faith, but rather as a justification of it. They don't feel threatened by it, nor are they compelled to resort to the "yeah, well, so's yer face" defense. They find the divinity in the miracle and diversity of life as it is, take their stories of creation as the tales they were intended to be (well, at least that's my hypothesis), and go on with their life.
Don't misunderstand me: your faith (or lack thereof) is your business. I'd say it takes just as much faith to say with certainty that there is no God as it does to say there is. We have no absolutely definitive proof, one way or the other. As a friend of mine said recently (after which, I told her I was gonna steal the crap out of this line), the plural of "anecdote" is not "data." If you have had an experience that validates your faith (for either side of this debate), that's cool for you. You probably know several people who have had personal experiences for which they determined the only explanation was that there is (or isn't) a God. It's still anecdotal. It still can't be quantified, qualified, and tested. So can we please try to separate faith from facts? Faith is about believing without evidence. That's fine. Do your thing. But please stop trying to tell people it's fact, that it's certain, and that you have proof, because it isn't, and you don't. That's what makes it faith. Accept what faith means, be cool about it, and let it go. There really doesn't need to be this antagonism between people of faith and people of science. People of faith can stop trying to tell scientists what they should be teaching, and scientists can leave people of faith to do what they will in their churches/gatherings/whatever.
Now, quit being so damned bitchy with each other, or I swear to the Flying Spaghetti Monster, I will turn this Internet around and we can all just go home instead of going to get ice cream.
Tl;dr: Faith is not fact. Theories are supported with evidence. Stop being rude and insulting in your conversations with people who don't agree with you.