Before I answer I should point to some of you that an agnostic person does not care for religion and has no opinions on the existance of a higher power, essentially if you do or don't believe in God you aren't agnostic.
Um, not really. Not caring for religion is apatheism, whereas an agnostic usually does care for religion in a small way. Agnostics certainly have opinions on God's existence, else y'know, that'd be going completely against its definition. Agnosticism has two main forms - strong/positive and weak/negative. Strong agnostics believe that it is impossible to know whether or not a God or Gods exist, while weak agnostics believe that the existence of a God is unknown but can be proved or disproved through science or philosophy.
tl;dr: "don't care" = apatheism, "don't know" = weak agnosticism, "can't know" = strong agnosticism.
I'm a strong agnostic, personally. There might be a God, there might not be, but I don't think it will ever be possible to prove God's existence or nonexistence. One can only find
evidence, not proof, for His existence., before people throw stuff like the argument from design at me. If I were to give a considered opinion, I'd say it was more likely that God does not exist, mainly because scientific evidence and philosophical evidence from people like Hume, Russell and Singer. The case for the defence is generally flawed. Every theodicy I've studied has proved to be unworkable and illogical, though the work of Aquinas and, to some extent, Anselm, does have some sway. (For example, we once had a debate in Philosophy, and my team, who were arguing in favour of Aquinas'
Quinque viae, managed to put forward a more convincing argument than those arguing against them. Even better, the judge was a devout atheist, who was visibly annoyed that he had to award the debate to my team. xD)
Oh, and could I make a request to everyone? Don't go around insulting people for their beliefs. Debate with them, fair enough, but don't make inflammatory remarks like "if you're a Christian you hate gays". It's not big, it's not clever, and it's not funny. It just makes you look like a dick. :)
Edit: Oh, and the same goes for any passing fundamentalists. Backhanded slights saying stuff like "you'll all burn in hell" or whatever is just as bad as people insulting your religion.