Trouble Ticket Systems

Dear Eric,

you wrote:

I'm looking for recommendations for a good trouble ticket system for a
NSP/ISP. Nothing fancy required, just somthing solid and easy to use.

Depends very much on what you want to do, what your needs are, who is
going to use it (inhouse, network operators only, anybody...)

I'd like to hear what others are using.

We are using Gnats - very simple, very easy, not quite what others may
call professional, but it works to our satisfaction and it was exactly
what we were looking for - ARS as commented by others did not meet our
needs and was too complex for our liking (hey, it is great, but not
the thing we wanted).
I read about two overviews you might like to have a look at:
- Computerworld, June 1992 (phone USA-508-879-0700), overview of 34
   trouble ticket systems (a bit dated)
- Moffit, M.L. and Rose, W.: Automating Your Software Support,
   SSPA, Software Support Professionals Association, 16981 Via Tazonsuite,
   San Diego 92127, CA (phone USA-619-674-4864),
   compares more than 100 Trouble Ticket Systems
(Actually, I only had a look at Computerworld and do not know the other