Question: According to Wikipedia

<http://en.wikipedia.org/wiki/Unix_directory_structure>

<http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard>

extra disks should not be mounted in `/mnt/` according to the first link, but doesn't seams so according to the second link.

Both say thought that they shouldn't be in `/media`.

**Question**

So where should extra permanent disks be mounted?

Answer: 
Wherever you like and where it makes the most sense for you. I have seen countless variants. 

Myself, I usually mount them at `/data0`, `/data1` or subdirectories below `/data` and put symlinks to the appropriate places (like `/home`).
SuSE had /srv as generic mountpoint for server-related stuff.

/var/lib/yourapplication seems to be a standard, too.

Since I use the automounter with fixed entries for these things, I tend to use /automnt.

The media automounted by UDEV (/media) is being redirected through CLAMFS (for virus scanning) to /extern on my workstation.

So short - there is no real standard - it`s up to you.