Ok, sorry for the harsh response, but i don't think that anyone is using it for "common purposes." Everyone should be using strong crypto, because it is inexpensive to do right.
I would argue that almost everyone that is storing passwords should start worrying about people bring racks of GPUs to bear against you, because it is so cheap. At 33.1 Billion MD5 hashes/s with 4 dual-linked GPUs (one machine), you can eat through all 8-digit alphanumerics very quickly for a few thousand dollars. (of course that is using PBKDF1 or less). I had done the calculations in a spreadsheet and forget how long it would take, but it is way shorter than you'd thik.
I would argue that almost everyone that is storing passwords should start worrying about people bring racks of GPUs to bear against you, because it is so cheap. At 33.1 Billion MD5 hashes/s with 4 dual-linked GPUs (one machine), you can eat through all 8-digit alphanumerics very quickly for a few thousand dollars. (of course that is using PBKDF1 or less). I had done the calculations in a spreadsheet and forget how long it would take, but it is way shorter than you'd thik.