I want to upgrade to a new motherboard so I can purchase a new graphics card. Will I have to reinstall Mandrake 10 as soon as I put the new hardware in? Can I just perform the upgrade function on the cd? If I have to reinstall is there any way to keep all of my programs and settings (last time I reinstalled I had to download everything over again)? Can I just put the new hardware in and let Linux 'detect' it?

You could try going the upgrade route. If that will produce a new initrd file that you need, you might be OK. Since the motherboard will have different hardware, different modules would need to be loaded. That means the initrd 'ram-drive' will need different drivers and a different script, and the /etc/modules.conf will need to be replaced. I'm not absolutely certain it will work, but the 'upgrade' option would perform this normally anyway because the driver versions would be changing if you were going up a version number for instance. Also, the /usr/local hierarchy shouldn't be touched by an upgrade. However, programs that you installed from tarballs may be need to be reinstalled.
( I'm assuming that you are not changing architecture, such as going from 32 to 64 bit processor ).

Actually I've done MANY a motherboard upgrade on an existing Linux install w/o a hitch. Even going as far as from a Pentium II thru Pentium III up to Pentium IV.

As long as the drives use the same controller mechanism after the upgrade everything else seems to fall into place.

Kudzu wakes up and sometimes asks about the new hardware. But otherwise it's pretty seemless.

MUCH easier than a motherboard upgrade in Windows.

You do have to do some minor reconfiguration, but it's pretty simple.

Remember to clear out any entries for hardware you have eliminated in /etc/modules.conf so that Kudzu can properly detect the new stuff.