Well, if your rig is an 88 as your screen name suggests, you SHOULD already have the bigger diameter spindles. That's not guaranteed though. If you do already have the big spindles, you'll need the following:
8-lug hubs (because you want 8 lugs, right?)
8-lug rotors (can't fit a 6 lug rotor on an 8 lug hub!)
Backing plates or caliper brackets (the same thing, just different names. Need them because the 8 lug rotors are bigger diameter).
Calipers should be the same. Some think there should be beefier calipers for the heavier axle, but instead they have more mechanical advantage by being on a larger diameter rotor.
Since you're sticking new hubs on your spindles, it's a fine time to replace the wheel bearings and seals too (wheel seal + inner and outer bearing).
Back to the spindles, it's a crap shoot. Supposedly there's a year change where both 1/2 and 3/4 Jeep&Chevy D44s all got the big spindles, but I've found the smaller diameter spindles on late 80's FSJ and 1/2ton chevies. Heck, mine had big on one side and small on the other thanks to some dipstick PO or mechanic along the way. That said, the spindle won't hang you up with the hub, those are all the same on the inner bore, but they use different bearings to fit the different spindles. AGAIN, you should have the big spindles already. The big spindles were used longer and more recently, BUT the smaller spindles keep showing up EVERY time I'm not checking for them, so just make sure before you buy parts or order bearings. Big spindles I'm pretty sure 2" diameter for the inner bearing diameter.
A agree that many overkill on the front axle. Before IFS, lots of desert racers would beef up a 44 rather than go 60 just to keep the unsprung weight down. Also, I don't have empirical data in front of me, but it seems that the most common failures for D44s are the knuckle u-joints (which can be beefed up with CTMs or the like) and the most common failure with D60s is shafts snapping because they taper down to the same diameter as D44 shafts at some point, don't they? So it seems to me, that a D44 with fancy u-joints has the same weak link as a stock D60 at a fraction of the cost and less weight. EDIT>>> For front axles only, obviously. SF rears are not in league with FF rears.