I just replaced my front shocks yesterday. The ones I took off were marked Motorcraft and were quite rusty, so they may have been 17 original years old.
I replaced them with Monroe-Matic+ ($25). And I noticed a very definite difference for the better.
If I had it to do again today, I would have maybe have gone to a higher-end shock for 2 reasons. First, the Monroe-Matic+ was a notably smaller bore shock than the OEM. Second, the better Monroe's and Rancho's are on rebate where you buy 4 and they pay you back for one of them.
I would also buy a couple of Dorman #31001 lower mount kits, and have the ability to grind a broken stud flat and drill a 1/2 hole in heavy gauge steel. The lower mount has a tendancy to snap off when you try to remove it. One of mine did just that, and it was an interesting recovery. The explorer really doesn't drive too bad with a missing shock... I was surpised. I drove it that way to get the kit, in town driving, no problems.
I have read here where you grind it flat and punch out the old stud. Mine would not punch out and I can say for sure I ground flush to the RA. I used an angle grinder to do that, then I did a progressive drill to get a hole to size but I didn't have a 1/2", so I got one from Orielly and it was a terrible bit. Dull out of the box. Thanks China drill bit maker. I ended up using a variety of tools in non-approved ways but it's in and all is good.
You will end up using a surprising variety of tools before you are done. If you have a friend with the big tool collection, I'd probably do it there. Good time to do brake pads if they are about due also.
Edit: Regarding the broken studs... I noticed that it's really not a matter of the nut being frozen on the stud. It's when you start trying to back it off over the exposed and corroded threads. If I had it again, I would get a wire brush or a wire wheel on a drill, dremel, whatever, and clean up the exposed threads first. Then, I'd use PB or acetone/tranny fluid. I don't think I would have broken it if I did some intelligent preparation.