Most servers today comes without a floppy drive.
If you want to install Windows Server 2003 on one of these servers and you have a hard drive controller that is not supported by default in W2K3 server, like most RAID controllers, the only way to install the driver through the standard setup program is from a floppy drive.
I have a floppyless server (HP Proliant DL140 G3) with the "HP 8 Internal Port SAS Host Bus Adapter with RAID" and I did not want to buy an USB floppy drive only to install the OS, especially after I read this post which says that you must use a HP branded USB floppy drive.
A HP forum search gave a link to this web site, where you can download a program called nLite, a "Deployment Tool for the Bootable Unattended Windows". Definitively recommended.
With this program you can make a bootable CD with you Windows setup files, integrate service packs and add your RAID drivers in advance so the controller is detected by Windows Server 2003 at setup time, without using the F6 option.
Edit on 2007/04/24:
I used nLite to install Windows XP on a floppyless ThinkPad T60 with a 120GB SATA drive and it worked like a charm.