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: 
According to the FHS link that you gave

```
 /mnt/  Temporarily mounted filesystems.

```

So I assume that you must mean permenantly mounted non-root non-system (meaning not /var/log or similar) filesystems. 

I've always put them in /mnt/fsidentifier and then symlinked to then where needed.

So for instance, I had /mnt/website at one point, /mnt/appdata, /mnt/whatever, then symlink that. I never mounted anything directly to /mnt

If you wanted a "clean" solution, you could write a script to take the UUID of the filesystem, create a mount point for it (under /mnt or wherever you wanted), then mount the filesystem to the mountpoint.
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.