Last time I checked you could get all keyboard upper and lower case rainbow tables up to 14 characters for $800. So you should look for something a bit over 14. Given that this stuff is exponential, the fact that those rainbow tables are 60Gb would suggest that maybe 20 characters is quite paranoid enough.
For LanManager hash's probably, because its actually 2 7 char passwords, old school (win9x days) method of encryption, still used for interpolarity IF your password can be encrypted with it (ie, all lower case, no symbols? and no more than 14 chars)... but this guy would HAVE to have LM hash's disabled, its stupid to leave them enabled on a all windows 2000+ network...

But for hashs such as md5 and NTLM/v2 (new school windows hash), 14 characters would either mean MASSIVE tables, or MASSIVE calculation time. its impractical, atm, to generate those tables, let alone the time it would take, even distributed efforts render these tables completely inpractical