Sigh. The bus transfer rate is completely and utterly irrelevant since that speed is only sustained for a few milliseconds before the whopping-huge 2-16 MB of cache runs out of data and has to fetch from platter again.
The sustained transfer rate of drives has not gone up dramatically in the intervening time -- back then it was around 40 MB/s for the fastest drives. Now it's around 70 MB/s for the fastest drives (71.8 for a 10K WD Raptor or 69.8 for a 400GB Seagate SATA) -- that's at the beginning of the disk. At the end of the disk it's considerably worse.
A) You'll notice, perhaps, that I said in my original post although drives don't sustain that transfer rate Perhaps next time I will post it in big bright colors.
B) (70Mbs-40Mbs)/40Mbs = 75% speed increase. Yeah you're right, that really didn't gain any speed at all.