Bored, so I thought I'd contribute to this a bit(sorry for full images if they cause issues, for some reason it's providing full size images even when I'm sure I entered thumb image links). Some healing factor feats.
From a YEAR ONE comic. Superman is wounded by a "daemon" and heals in an unspecified time, but Doctor Occult says he heals fast.
This one technically happened in an alternate universe, but what the hey. He gets cut by 2D versions of the Royal Flush Gang, and seems to heal rather fast.
Here, Supes takes Kryptonite and damage from Metallo, and when a scientist says he needs medical attention, he says the Sun will heal him. Though he's still bruised, he's better enough to stand on his own a panel later.
Has a Kryptonite bullet in him, Superman is still healing the wound quickly enough that Batman isn't sure if he can remove it in time.
Superman previously had been hit with plastic explosives, and taken deadly(for normal people) electricity, while still having the Kryptonite bullet in him. After it's removed, under apparently yellow solar panels, he's better pretty fast.
Superman has the iron in his blood turned into Kryptonite, then gets run through with apparently a Kryptonite sword. He's back in the game pretty quickly after it's removed. Some might argue its continuity, as time was being messed with(though they changed things back, so it didn't seem to actually be an alternate universe or anything).
Gets his throat slit by Kryptonite Man possessed Batman, still heals it while exposed to Kryptonite radiation, and fighting Batman.
Has his throat slit by Wonder Woman's tiara, we see in a follow-up comic he's healed it pretty quickly.
These next two aren't quite Superman, but I think are valid(with context disclosed) and worth including.
Here, Jor-El(or, an alien altered to genetically be Jor-El, so what counts) comes to Earth injured and burned. We see with just a short time in sunlight, he's healed his injuries quite well.
Here, Superman is having to deal with both Paragon and a bunch of Daxamites at the same time. Paragon gets annoyed, shoots a bunch of them, and they attack him. Paragon has internal injuries according to Superman. Paragon is using Superman's healing factor, although enhanced. Since Paragon's power is to copy but enhance the powers of others. It was never clarified how much Paragon enhanced their powers, but he didn't seem too above Superman.
Superman had fought Gog, been impaled and injected with liquified Kryptonite, and still fought a while(with help from Connor).http://s1199.photobucket.com/user/Delta1938/library/Superman%20VS--/Villains/Gog/Gog%20II/AC%20815http://s1199.photobucket.com/user/Delta1938/library/Superman%20VS--/Villains/Gog/Gog%20II/AC%20816
And it weakened his powers(at the least his durability). He was to the point conventional bullets went through him. Fought Weapons Master getting shot multiple times, stabbed once or twice and almost drowned.
And shortly after that, he intimidated some villains, then passed out. In three days, he recovered from significant injuries despite his powers being weakened, cutting in and out, and no direct exposure to sunlight it seemed.