If you want to see a really scary BIOS you have to have a look at AMD's Fester-board. Due to the fact that this board is for reviewers and OEMs only, AMD included a huge amount of tweaking features to run Athlon at its best. You will see that none of the three retail-boards comes with as many features, but they are still performing just as good as Fester. Here's a look at Fester's toughest BIOS-screens:
This is the 'K7 L2/MSR/Workarounds' - screen. You won't find anything like that anywhere else and I guess there's not much point getting into all those settings, let alone the fact that I don't understand all of them myself.
Screen No.2 is dedicated to 'Irongate/AGP Setup' and includes a ton of SDRAM-settings, which you will find in the other BIOSes as well.