I'd probably go with 1985.

Yes, its sentimental to me, being the year I started reading comics, but looking back, it's also the time when things still seemd to be "on the rigth track" meaning going back from that point, MOST of it all seemed to still be "in character."

Peter Parker was single and still had some problems. The X-Men had not yet fallen into the dissarray they've been in since then, the Avengers were still Earth's Mightiest Heroes and still led by Cap. All the basic pieces that made the Marvel Universe great were still in place, and the best generation of post Lee/Kirby/Ditko creators had just recently left their most impressive marks on the characters (JB's FF and X-Men, Miller's Daredevil, Simonson's Thor, etc.)

Over at DC, Batman hadn't yet become the post-DKR psychopath, the JLA was still a very exclusive group consisting of DC's best archetypal heroes, etc.

In the several years following that period, everything seemed to start spiralling out of control.

Superman, it would be somewhere where Simonsov-Bogdanove left Superman. Then it started to decline and he is "dead" for me. Restart there. This is to me the point where JB's Superman left us. Not because everything was perfectly the way he outlined it or wanted it, but because the writers after that didn't even care about MoS anymore.

The DC universe, right before the solution of Zero Hour. It was the worst solution to a drama ever with the Green Arrow crying and waling home on a New York Street. The idea was good wih the white clouds but skip Grene Latern/Parallax.

The above are the worst problems with DC.

Marvel then, Spider-man, the worst period was when he got married, before and after. so it will be way before that. Marvel in general way later, let's say that before it became M***** or what you call it, when they fired (?) an artist we love, you know who, I guess around there.

Batman, when the comics didn't look like Neal Adams' Batman any more, mid 90's or so, I can be wrong here. Before Bane I guess. but I know too little.

Legion of super-heroes. The 70's era was the best era. The first version was the only version, they should go on without Superboy. For a while they did something with them five years older but it wasn't that great. But the idea was good.

So, we're not talking about time-travel, just a reset button.  No one's taking your JB FF's away.  That being said, could the bulk of comic creators today maintain that "reset" for very long?  Let's just say it'd work, for the sake of argument.

I think 1976 would be my "magic" year, as well (not coincidentally, pretty much the year I really started enjoying comic books). 

A "Strongest one there is!!" Hulk - it wasn't that he healed fast, it was just really hard to serioulsy hurt him!  The tragedy and irony of the Hulk:  here was the strongest mortal on the planet with a mind of child, Bruce Banner's curse of a rampaging alter-ego that was also a hero - you wanted Banner to find happiness but it seemed the world was better off with the Hulk in it.

A Spider-Man that's had a clone, but the situation was resolved neatly in a few issues. 

The Fantastic Four, Avengers, and Defenders all seemed to have less than 20 members each.

A still earth-bound Silver Surfer;

And Captain America, alive, respected, and without a utility belt.

The first Marvel/DC crossover....

And I was always more of a Marvel guy, but '76 would be okay for a DC reset, too.  Though I think that knocks (Earth-1) Clark Kent out of the Daily Planet and may make (Earth-1) Wonder Woman powerless.  But otherwise, good times.

For Marvel, right around the time of Secret Wars II.

For DC, immediately before Crisis (and there would be no reboots of any characters in "my" DC).

This one has been hard for me because I've been trying to think of not "the year I was enjoying comics most" but "the year the comics were the best." Not necessarily the same thing.

I think I would go with (and my calendar might be a bit off here) 1969.

DC: Batman was getting revitalized with some work by Neal Adams (tho the big changes, working with Denny O'Neil were still a year or so away, right? and GreenLantern/GreenArrow was in the future too), the thinking was starting on working on Superman (tho those changes were coming the next year), and the whole line was feeling pressure from the competition and having to show what they could do.

Marvel: Stan Lee was still active, Kirby was still King (leaving for DC this year or '70?), Romita on Spider-Man, Adams crossed the street to pump some life into the X-Men, and the whole line was kicking butt. 

I have always been more of a DC person (tho there have been some trying times), but I wonder what it would have been like had Stan and Jack worked things out.

(And if I answered for what year *I* enjoyed it the most, it would probably be 1978, which amongst other things was the year I discovered JB.)