Probably I'll preorder one as soon as possible regardless of the games.
If I don't want it at launch, I can still cancel the preorder or sell it with a slight profit.
Worked for me, when the PS4 launched and most of the games I wanted were delayed:
In November 2013 I got the preordered PS4 for €399 and sold it through for €565 (minus €51 eBay and shipping costs).
In February 2014 my preordered Killzone-PS4-bundle arrived for €504 (including KZ: Shadowfall, a second DualShock4 and the PS-camera) and sold that extra stuff for a total of €145 (minus €12 eBay and shipping costs); of course I played through the game first.
Normally I would have canceled the preorder of the first PS4, but that would also have canceled my preorder of DriveClub for €20.
So eventually I got my PS4 in February 2014 for €256 and DriveClub at its release for €20:
399 + 504 + 51 + 12 - 565 - 145 = 256