K7S5A is great, but with KT266A on the horizion (Next week as a matter of fact), There's 3 confirmed boards using it, but there's gonna be loads more. The best will probably be Abit KR7-RAID. It's been in development for 6 months, they've been waiting for KT266A and now it's finally here. Another good board should be EPoX 8KHA+. The current 8KHA (using KT266) is a nice board on it's own.
<< and would an AMD chipset always work best with an AMD chip? >>
That used to be true with Intel CPU's but never was the case wityh AMD CPU's.
On the chipset. A chipset is basically what connects all the different parts of the computer together. A Chipset comprises of 2 Chips on the mobo, traditionally called the North and South Bridge's. The North bridge houses the Front Side Bus to the CPU, the Memory Bus, the AGP Bus (Video Card Bus), and in traditional chipsets the PCI bus (The bus for the White expansion slots on the mobo) is used to connect the 2 Bridge's, and then the Bus would continue to the PCI slots but now in modern chipsets there is a dedicated North-South Bridge connection. VIA's is called V-Link, SiS's is called MutIOL, ALi is using HyperTransport, etc. On to the South Bridge. The South Bridge in modern chipsets that uses dedicated connections to the North Bridge, houses the PCI Bus, On-board AC'97 sound codec, USB Ports, etc. So there you have it. The main 4 chipsets for the Athlon for a while will be VIA KT266A, SiS 735. ALi MAGiK B0, and nVidia's nForce.