I hear this one all the time:
"Buddhism is a religion".
Ha! An interesting post! My knee-jerk reaction is to get defensive and say, "RAAAAH! Of course it's a religion!" but like a koan, this post points to many interesting things, I think.
I suppose the answer mainly depends on what your definition of "religion" is. If you look at things from an external perspective like an anthropologist, you can ask if Buddhism possesses some of the general features of what most people consider to be a "religion": Does Buddhism have its own holy scriptures? Yep. Does Buddhism worship some type of god or gods? Er...only sort of. Does Buddhism have prophets and other holy men? Yep. Does Buddhism have its own places of worship and holy sites? Yep. Does Buddhism have its own rituals, prayers, and chants? Yep, yep, yep. Does Buddhism have its own marriage ceremonies? Interestingly enough, not really. Does Buddhism have its own priests or monks? Hell yeah!
So, Buddhism seems to fullfill most of the social functions of a typical religion, but the subtle details of Buddhism's beliefs make it very different from other religions of the world.
I once read some lamas and perhaps even Zen priests say that there is no need to call Buddhism "Buddhism" or a "religion" or any label whatsoever. Function matters over form, I think. All labels are empty of any intrinsic existence and only have the meaning we assign to them. The wisdom of Buddhism transcends all labels.
Wisdom is wisdom, and it just so happens that the deepest wisdom which allows us liberation from samsara and the ability to liberate others is this thing we call "Buddhism."