We saw them before, now let's look at some more. Here are the fight's we'll probably never see for one reason or another, and it's a shame.
This list is a little different in that a couple of these crossover fights have actually been done in the Marvel vs. DC miniseries they put out a few years ago. Unfortunately, they weren't given the proper respect they deserved simply because of the sheer volume of heroes and fights they were trying to plug in those books. That being said, let's see a rematch or two!
Zatanna vs. Scarlet Witch
On the one hand, you have a one of the most powerful magicians in the DC universe. On the other side, you have a reality-bending mutant who was single-handedly responsible for the whole "House of M" storyline. Scarlet Witch's powers have grown substantially from what they were when she was originally introduced as a mutant with hex (or "bad luck") powers. As such, who knows what she's capable of anymore?
I don't know how you'd call this one, other than just to say it would be close. Zatanna's weakness is that she has to speak her magic to make it happen. If the Scarlet Witch found a way to stop her from talking, Zatanna would be in trouble. On the other hand, Zatanna is a trained fighter, so if she could get in close enough she could still do some damage if need be even without the magic.
Huntress vs. Elektra
Two of the toughest ladies in comic books today would make for an excellent battle. I know Elektra's current whereabouts are unknown thanks to the Skrulls, but when she returns (and she will) this would be a great fight.
I know most folks would pit her against Catwoman--and they did fight in one of the Marvel vs. DC comics--I would prefer to see her go against Huntress.
Elektra definitely has the mad ninja skills going for her, but Huntress has trained with Batman, and that couldn't hurt. The longer the battle went on, the more likely Elektra would win, so it would be up to Huntress to finish this one quick or not at all.
The Punisher vs. Deathstroke
I know I used Deathstroke in a dream fight last time, but come on, this one is a no-brainer. The only question here would be how many rounds of ammo could be used up before one took out the other.
Deathstoke's enhanced abilities give him a slight edge here, but Punisher is a seasoned warrior and won't be taken by surprise. He's also a serious sniper, so there's no reason to think he wouldn't go long-range with this and attack Deathstroke before he even knew the fight was on.
Doctor Fate vs. Doctor Strange
Another trip to the mystical side of heroics, this match-up would be epic just in scale of what both men could do.
Both men are considered one of the most powerful mystics in their given universes, and yet both are little more than human.
I think this fight would just be a constant battle of oneupsmanship, with one throwing a spell on the other, him breaking out of that spell and throwing his own back, and so forth. I don't see anything that puts either man at a distinct disadvantage, and the only way I see this ending is with some form of outside interference.
Sentry vs. Gladiator
We may still see this one someday, but for now it's just speculation. Both are blatant Superman copies, and are powerhouses in the Marvel universe.
As far as weaknesses go, Gladiator is affected by certain types of radiation, which could possibly be used by Sentry to even the fight. Also, some of Gladiator's powers are weakened by a lack of self-confidence, so if he finds himself taking damage from a few of Sentry's punches he might start to weaken there as well. If Sentry cut loose on him (as he did on the Hulk in the World War Hulk finale), it might be enough to finish him.
On the other hand, if Gladiator told Sentry he was the Void, Sentry would fly away crying. Fight over.
And what would this list be without a team battle...
Secret Six vs. The Thunderbolts
The battle of the "villain hero team" from both publishers. Now this isn't necessarily the greatest run since both teams are in flux right now, but let's say it's the recent glory days for both teams. The Secret Six lineup would be Catman, Deadshot, Scandal, Ragdoll, Knockout, and Mad Hatter (from the Secret Six miniseries). The Thunderbolts would be Venom, Bullseye, Green Goblin, Moonstone, Songbird, and Swordsman. The possibilities would be great.
Knockout versus Venom promises a lot of action. Bullseye versus Deadshot alone would be a fight worthy of its own miniseries. Catman versus the Swordsman...Ragdoll versus Moonstone...Scandal versus Songbird...and then Mad Hatter takes on the ultimate trip to Wonderland: Green Goblin.
Unfortunately, Knockout is dead thanks to Birds of Prey #109, Mad Hatter hates the team thanks to Ragdoll's betrayal of him at the end of the Secret Six miniseries, and Venom is sort of in a weird place right now as Scorpion/Venom, so we'll never see this one. Still, you have to admit it would be a great confrontation if it was done correctly. Both sides have no compulsions against killing when necessary, so it could go either way.
I'm open to suggestions for future lists. What comic book issue keeps you up at night?