OK, thanks. I'll assume it's just a USB device (there's a couple of Flash card readers that do not normally have a disk inserted). For the sake of completeness, here's my current fstab. Thanks to everyone for their assistance and comments.
/dev/hdb5 / ext3 defaults 1 1
/dev/hdb1 /boot ext3 defaults 1 2
none /dev/pts devpts mode=0620 0 0
/dev/hdb8 /home ext3 defaults 1 2
//neil/NEIL-CDROM /mnt/NEIL-CDROM smbfs user,username=% 0 0
//neil/NEIL-D /mnt/NEIL-D smbfs user,username=% 0 0
//neil/NEIL-E /mnt/NEIL-E smbfs user,username=% 0 0
//neil/NEIL-F /mnt/NEIL-F smbfs user,username=% 0 0
//neil/NEIL-H /mnt/NEIL-H smbfs user,username=% 0 0
//neil/NEIL-I /mnt/NEIL-I smbfs user,username=% 0 0
//neil/NEIL-J /mnt/NEIL-J smbfs user,username=% 0 0
none /mnt/cdrom supermount dev=/dev/hdc,fs=auto,ro,--,iocharset=iso8859-1,codepage=850 0 0
none /mnt/floppy supermount dev=/dev/fd0,fs=auto,--,iocharset=iso8859-1,sync,codepage=850 0 0
/dev/hda1 /mnt/win_c ntfs iocharset=iso8859-1,ro 0 0
/dev/sdb1 /mnt/win_c2 vfat iocharset=iso8859-1,codepage=850 0 0
/dev/hdb9 /mnt/windows vfat iocharset=iso8859-1,codepage=850 0 0
none /proc proc defaults 0 0
/dev/hdb7 /usr ext3 defaults 1 2
/dev/hdb6 swap swap defaults 0 0