I use mostly Sony AIT solutions including a standard model that can hold 50GB uncompressed and a 4 tape autoloader (200GB before compression). Compared to the HP DLT I have they are a pleasure to work with as the tapes are less than a quarter of the size, the performace is as good or better and they never need cleaning. However they may be a bit expensive for a small office etc (best part of £1000 for the standard drive).
For software I use BackupExec 9 with a few extras like Exchange and SQL support.
Regards
ed