if youre buying a pci ide controller, you might as well get a 133, unless it is like twice as expensive or something stupid like that....for drives, worry more about access time, and overall performance. ata/133 means nothing about how the drive performs. a 5400rpm drive at ata133 is stupid, a 7200rpm drive at ata100 would be much better. so if the drive you want has ata133, then great, but dont make it a factor in your purchase. current drives max out at about 40MB/s sustained transfer.
theres not even really a difference between ata66 and ata100 most of the time....i am using ata66 on my asus a7v133 because the ata100 controller makes the boot take longer and i dont notice any speed difference, and i'm using a ata100, 7200 maxtor drive that was the fastest available (maxtor) before the current 740dx, so its not a pokey drive as far as ide drives go, and like i said, i didnt notice a difference.