I put Debian on the Monarch system. The Thunder K7 has two 3Com 3c920 Ethernet interfaces built in, which saves having to play “What version of the EtherExpress Pro 100 is Intel selling today?” But my current install CDs don't support the 3c920. This is a common sort of problem when installing on the very latest hardware, and you can deal with it two ways: either move your drives to an old machine and install everything there, then upgrade; or, do what I did and put a Tulip card on the new system to get a new kernel (I got 2.4.8) installed and working.
Another post-install dance is upgrading to ReiserFS. Install on the second drive, upgrade the kernel and compile in ReiserFS support, make a ReiserFS filesystem on the first drive, boot from a LNX-BBC rescue disk and copy everything over to the first drive. Then reboot with the first drive as root, fix lilo.conf, make a new ReiserFS filesystem on the second drive and mount it as /home. Not as hard as it sounds if you are familiar with the LNX-BBC disk.
Why two drives instead of one big one? The ReiserFS trick is one reason, and kernel hacker Andre Hedrick says that if you want maximum performance, don't partition any disk. The kernel's “elevator” algorithm for ordering reads and writes doesn't handle partitions well.
If you have one partition spanning cylinders 1-500, and one spanning 501 and up, and one process writes to cylinders 1, 2 and 3, while a second writes to 501, 502 and 503, the kernel will write them 1, 501, 2, 502, 3, 503—in logical order instead of physical order, which is sub-optimal.