I was using it as simply a second workstation while my main workstation was down, and one that my girlfriend could use while I had my laptop and tablet with me. However, I wouldn't mind putting it to more well-deserved uses, like an LDAP server, backup server, db server, etc. So, I was wondering what all the sparc experts out there think an Ultra 5 would be well suited for :)
I was using one as a management box until recently - installed Sarge and nagios - it was plenty fast enough for the job.
I have also used one as a slave DNS/Mail server.
In the case of a backup server, I have a connor raid box I was considering connecting, but I think the hardware limitation on this particular box is 12GB, so it might not be worthwhile (I do some dv editing on my main machine,so I have several hundred GB's of data).
The IDE limitation is 120GB (ish) - however, this does not mean it wouldn't be a useful backup box - stick a USB card in, very cheap these days, and attach an external drive. Or pick up a cheap SCSI card - about £20 from eBay and one of the 7 or 12 slot external enclosures and have yourself a nice RAID backup :-)
The Ultra 5's (and 10's) still make remarkable good workhorses in these days of multi-core, multi-gigahertz machines .... they make wonderful development boxes too...
HTH. Cheers, Pete.