My main keeper league is about to go into its 4th year and I've won the league each year it's been in existence.
In our original draft I was able to snag A-Rod, Beltran and Prior and made a trade for Soriano later in the year. Those 4, along with Schilling, comprised the 5 I was able to keep.
For last year's draft the keepers was reduced to 3, so I just wittled off Prior and Schilling.
The point is, for me anyway, I've been fortunate in that I've had the foundation of young studs that it allows me to take a chance on older players that might slip, because while other owners are trying to grab up the young keepers, I can look at the older solid vets who will help complement my already golden young guys.
So depending on how many players you keep, make sure you get a core foundation of guys you can count on for years to come and then you'll be able to complement them with nice veteran picks.