Where do you store data files?

[logistix]

I've got a project that generates a simple text-format database and
will probably generate a few dozen more documents for caching
purposes.  I'm just trying to decide where I should store them.  I was
thinking about just creating a subfolder in the module, which is fine
for Windows but doesn't seem to be the "appropriate" Unix place to
store it.

Just wondering what other people were doing.