for chipset drivers technically you can select all of them (except the ones that conflict, like multiple nforce or ICH kexts. But this is generally if you don't know what chipset you've got.

For you, though, seeing as how you've got the SB400 chipset I'd recommend the VIA/SiS/Marvell/SB Chipset Drivers. if you experience any problems with this search around as you can update the kexts after you install (from the DVD if need be).

---