Pretty much the Fall and Rise of the Avengers. These three arcs are surprisingly uneven, with the one about the formation of the New Avengers being the best and the one about Sentry being the least. On the plus side, we see Bendis' penchant for ideas, and on the minus side we see his fights that go on for too long. 
 Disassembled! (500-503) This is a story where I can understand why some people don't like it, but I generally disagree. Yes, this was a notable change in the Avengers status quo and some well-loved characters died during it. (I actually have more problems with the roll-backs of every single one of these deaths in the years since.) 
 However, this was also an exciting and shocking story that concluded with a moving remembrance. It set the path for years of interesting, innovative, and different stories that wouldn't have been possible with the *old* Avengers status quo, and in the process it totally reinvigorated the franchise. [7/10] 
 Breakout (1-6). Avengers: Disassembled was very exciting, but shallow and ham-handed. However, the point was to get here, and Breakout is quite good. 
 Bendis' idea of bringing together a new Avengers team by fate, just like the original, is genius. But even more genius is bringing heroes like Spider-Man and Wolverine into the team. Today it seems old hat, but that's because it was so successful. Though these two characters aren't currently involved in the Avengers, the team(s) have been much more diverse than in Ye Olden Days. You can trace the Unity squad and the inclusion of other non-traditional characters all to this single story. 
 As for the plot: Bendis handily connects up a few major plotlines, from a prison break to the Savage Land, keeping the story from being too decompressed. The prison break is also very exciting, like Disassembled was, but by the time we get to the Savage Land, a nice mystery is developing about what's going on with the powers that be. 
 One last thing: this comic has humor that shouldn't be underestimated. It's sometimes laugh-out-loud funny and it's generally a nice change of pace for the Avengers. [9/10] 
 Sentry (7-10). This is a story in two parts. On the one hand, we get the continued story of the New Avengers coming together. There's a fun fight against the Wrecker and the whole team really gels. It's great. But most of this volume is taken up with the Sentry, and his whole great-hero-who-was-forgotten bit. Nowadays, it's overdone, but even at the time this story was dull. That's in large part because it's not actually a New Avengers story, it's a Marvel universe story, and there's way too many people to have much characterization [5/10].