Depends on if you boot from CD on occasion (Ubuntu or Knoppix users) or are frequently installing multi-boot operating systems.
I usually go with CD-ROM, then hard disk. I haven't had a floppy drive for years anyway. On the "waiting for the CD to time out" issue, a CD-ROM is smarter than a floppy drive. The floppy disk only knows if there is a disk present by trying to spin it up and read it. The CD-ROM can tell if there is a disc present without having to spin up the drive, so the "time out" interval is much slower than you would think. Plus, most people that I know only reboot their PCs once every couple of weeks so any delay would be largely irrelevant.