I'm Newbie with Linux so please keep it simple.

I have 160GB external Lacie USB HD, which I've been using for some time, having ntfs file system. I installed ntfs-3g (R/W ntfs driver for Linux) acc to these instructions
"ubuntuforums.org/showthread.php?t=217009"
and the R/W started to work fine with the HD (damn, I should have stopped here).

During the the ntfs-3g installation I created a new directory /media/Lacie160 to which I mounted the HD in fstab:
/dev/sda1 /media/Lacie160 ntfs-3g silent,umask=0,locale=fi_FI.utf8 0 0
So everything was fine at this point.

Then I noticed that there was already similar directory "/media/Lacie" (obviously generated earlier by Ubuntu) so I decided to do some clean up and deleted the "Lacie" and renamed the "Lacie160" to "Lacie" (and of course changed the name in fstab), I shouldn't have done this, now Ubuntu shows that directory "/media/Lacie" is empty and I cannot read (find) the HD anymore.

What should I do to make the HD visible again?

Have you tried reversing the steps you took? Rename /media/Lacie back to /media/Lacie160, edit fstab, then recreate /media/Lacie

Ok, I'll try the reverse step method.

Does Ubuntu create some hidden files when it creates the /media/Lacie directory during the first plug-in of a USB HD, in this case they are gone now for good, or is it just a dummy empty directory?

I'm not too sure myself as I typically run Slackware, but I can check on a Ubuntu box at work today. I have a flash drive that I've never plugged in to it, so it should create the folder and such.

My gut feeling is that it's just an empty directory, otherwise mount would complain if it was used as a mount point, but the drive might be mounted somewhere inside /media/Lacie. The problem is that Ubuntu doesn't use fstab for auto-mounted drives, so your current fstab conflicts with this.

I got it visible again. I tried first the reverse thing, didn't help, but when I removed the mount line from fstab and booted Ubuntu the Lacie icon reappeared on the desktop. I just have to rethink the mount method, I'll let you all know how it goes.