[snarke]

No, that looks like something had been writing to your external hard drive and it got unplugged or dismounted, so said program created a real directory in your /volumes folder. Now when "IOMEGA HDD" is mounted, since there's already something named that in /Volumes, the real drive gets the "1" stuck after it.

Disconnect all external drives, eject all CDs, dismount all network shares, et cetera. If there's anything in /Volumes, that's probably a lingering error of some kind, and needs to be deleted/moved.

If you really had multiple partitions on that drive, say "Iomega1" and "myHDD", then you'd find
iMac-G5:/Volumes/Iomega1/
and
iMac-G5:/Volumes/myHDD/
The device itself won't appear in /Volumes.