2. What do you recommend as the least amount of available disk space that an XP system should have to run optimally?
According to microsoft's site, 1.5GB is the minimum requirement for an XP Pro installation.
They also say it will run on 128MB of RAM... but don't you believe it. Unless you want it to emulate the boot speed of Windows 98 on a Pentium 1. ;-)
My system at home is 1GB RAM and 60GB OS Partition. Keeping in mind that windows updates and so forth eat up hard drive space; the swapfile eats up space; installed applications eat up space.
Just because software comes on a CDRom (such as XP), don't assume that all the space it's going to take is 640MB. Files are compressed, swap files created, etc. etc. etc.
If you want your system to run "optimally", do what I did... get a large hard drive (I have a 160GB), partition it (60GB OS, 100GB applications/data). This way, the FAT table won't be HUGE for your operating system, and if the OS crashes and needs to be re-installed, your data is still safe on the other partition.
Just my 2¢
"What the captain doesn't realize is that we've secretly exchanged his dilithium crystals for new Folger's Crystals." -- My Sister
--Greg