Bob has a password (for his WPA encrypted wifi) which is 8 characters, all lowercase, and not a dictionary word.
Eve lives next door to Bob and wants to illegally hack his WPA. The number of possible passwords is 26^8 (is that right?).
EDIT: The ssid is not common, and there is no rainbow table available for it.
How long will it take Eve to brute force that password if she has a: a regular desktop machine from 2011 b: a powerful desktop, with GPU (does GPU help at all in this case?) c: a GPU cluster of 8 cards d: access to amazon cloud GPU clustering and a couple of hundred dollars.
The UK's only cable ISP (Virgin media) provides a combined modem / wifi router. This is supplied with an SSID of the form "virginmedia1234567" (The word virginmedia with a 7 digit random number), with a random password of the form "abcdefgh" (8 lowercase letters). I have this router, and have changed everything. Many neighbours also have this router. I have no idea (and I'm not going to try to find out) if they've changed their passwords.