To rebut Wolfman's evolution argument briefly, as new evidence is uncovered, new arguments can be made. Darwin's theory sounded interesting when first proposed, but when Mendel's work was (re)discovered, a stronger argument could be made for its veracity. I don't think we have discovered everything there is to know about evolution yet (leaving abiogensis out of the question for the time being).
And I'm sure that a theist would respond that there are new "miracles" and other such events always happening that would constitute "new proof" or "new arguments" for their beliefs.
Come on...ask 20 different atheists/scientists, separately, to list their key arguments to "prove" evolution, to demonstrate its truth. I'll bet you that those lists would come out looking almost identical. Would that, in any manner, shape, or form, serve as an indication or 'proof' that those beliefs were not valid? Of course not.
In fact, to take this a step farther, I'd argue that the OP is completely wrong. That the weakness of "religion" is not the fact that they always use the
same arguments, but that, in fact, they use too many
different arguments, many of which are in direct opposition to each other. Try putting an animist, a Hindu, a Buddhist, and a Muslim together to come up with a unified system of arguments for their belief in some kind of god...it'd be virtually impossible.
There are far, far,
far more arguments used by various theists to justify their beliefs, than there would be arguments used to justify evolution, or most other scientific theories.