there are numerous times when you might need a floppy drive but yes, you can set any bootable device (cd-rom, usb device, etc.) as the first boot device in your cmos.
and no, you do not need a floppy for the first boot as long as you have a operating system installed on your hard drive or a bootable medium (such as a bootable cd for a cd-rom or a bootable floppy in your floppy drive) in your first boot device.