The only real way I draft keepers differently is that I may slightly favor a player who will give me durability next year as well.
For instance, Clemens is pitching lights out right now. In any normal midseason draft he'd be a pretty high pick.
But I wouldnt necessarily take him highly in a keeper...who knows if he'll be around next year, or how effective he will be.
Same thing for say, Pedro Martinez, who is having a resurgance this year but is injury-prone and getting older. He's nice this year, but would you want to waste a high pick on someone like that?
On the flip side look at Clint Barmes, who is having a good season right now, but is also poised to star for years to come. He'd probably go higher in a keeper draft than a regulr midseason.
Hope this helps.