i have actually tried timimg boot ups, and certain programs launching, or carrying out commands that seem to be disk intensive, and there is a real difference. noticeable from my clients who have called to thank me profusely. (they tried adding ram and there was some slight improvement, but the 7200 h.d. was a bigger improvement.)
i wrote this post because i an't find any info on real world h.d. rotation speed, versus udma mode improvements). i guess what I am trying to say is that ata-66 is hyped(who cares what burst speed is?) because latency and seek are the real bottlenecks and the 7200 which has a stated same seek and latency(?) is better at both. which begs the question, are we going to need 10000rpm ata100 drives to show any improvement? or is the real improvement in the rpm rate/