7. "Blood on the Moors" Captain America #253-254
Captain America goes to England where he teams up with his old Invaders buddies to take on Baron Blood. If this storyline only introduced a brand-new Union Jack, it would likely be well-remembered as yet another excellent Roger Stern/John Byrne/Joe Rubinstein Captain America adventure. But this one went one step further, with one of the great Cap fights of all-time...
What an amazing piece of storytelling.
6. "Captain America No More" Captain America #332-350
Mark Gruenwald teamed up with a young Kieron Dwyer (inked by Al Milgrom) for this epic storyline, where Steve Rogers is stripped of his shield and the secret identity of Captain America. The government appoints John Walker, the jerk known as Super-Patriot, to be the new Captain America and they assign him his own Bucky, although quickly changing it to Battlestar once they realized that calling a black guy "Bucky" was offensive. Steve Rogers, meanwhile, teams up with his old friends Falcon, Nomad and the new hero, D-Man, to fight crime under his own identity, the Captain.
Gruenwald masterfully wove together the two competing stories - the new Cap and Battlestar making their way as new heroes while the old Cap and his pals fought bad guys on their own terms. It was here, too, that Diamondback really started to remake herself to be "worthy" enough of being Cap's main squeeze. The most memorable mini-arc within the overall epic story is when Viper tries to turn the people of Washington D.C. into snakes, including Ronald Reagan himself!
Here's an example of how Gruenwald balanced the two simultaneous narratives...
By the end of the story, Steve was Cap again, but we gained a few new heroes, USAgent and Battlestar. It was a very satisfying epic arc. Well-crafted by Gruenwald, Dwyer and Milgrom.