I asked the Lynx sound card folks and the Wavelab software folks and the Wavelab developer said his 10k drives work well(But, he is the Wavelab developer! HE may need them and if he doesn't, who cares? He can at least afford them.), but the Lynx guy said that unless you "need" them for some reason(Hard to say what? Loads of tracks and tons of plug-ins?), you may see no improvement - though I would think(Me, not the Lynx guy)they "should" be noisier and run hotter??? That said, I wouldn't go back to my 5400 rpm drives from 7200, but I don't know why not, I remember no "wow's" when I upgraded - though those 5400's that still work are really old and dusty now so I don't really want to go back... My next drives, for my meger work will be 7200 rpm SATA's and "small" ones at that(I'd rather 10 80 gig drives than one 800 gigger.)
ALL THAT said, if budgetarily they're not a problem and if you want them, why not? If money was no object I'd get 'EM!(And the "dual processors" to go along!!! And FOUR gigs of RAM!!!!!!) On the other hand if you don't know why you need them you probably don't. Worthless? For many, 2 gigs of RAM and 2 300 gig HD's of any kind are "worthless", but, hey, it's all so cheap today and it probably doesn't hurt...
I hate to ask, but, what is "DFD"? I can make-up of lots of things with those initials though I guess ...? No. Probably not.