Let me see...
From the Avengers side:
- Dark Avengers (An Avenger team comprised of Norman Osborn, Venom, Bullseye and othe psychos? It's awesome)
- Captain America ( The Brubaker Run, read it all, it's very, very good)
- Iron Man: Extremis, Director of SHIELD, World's Most Wanted, The Five Nightmares, Doomquest and Demon in the Bottle
- Ms. Marvel: The New One, and the old one too, specially in Dark Reign, where we had both Captain Marvel and Moonstone as leads.
- Hawkeye (The Matt Fraction run, it's just that good)
- Black Widow (Marjorie Liu's run)
- Hulk ( Planet Hulk and World War Hulk)
- Young Avengers (EVERYTHING!!!)
- Secret Avengers
Thunderbolts (Really, every run is entertaining to say the least, but both the New Thunderbolts run, the Warren Ellis one. The classic Thunderbolts 1-75 is really good as well. The only run i didn't like was the last one, where instead of villains the team is a bunch of anti-heroes.)
Street Heroes:
- Alias
- Spider-Man (Spider Island is very good, The Sensational Spider-Man Annual #1, Spider-Man: Blue)
- Daredevil (Daredevil: Yellow, and Daredevil V2, all of it, really, very good writers in an amazing run)
- Punisher (Punisher Max, all of it, and...Anything Punisher written by Garth Ennis is awesome)
- Runaways (EVERYTHING!!1!11!)
X-Men
- Uncanny X-Men( The V2 is really good, Kieron Gillen was one of the reasons that even when Cyclops was the villain of AvX, the readers where rooting for him, the Utopia arc is very good as well, but to follow it, you have to read both UXM and Dark Avengers, Messiah Complex, we can go classic here as well with the Phoenix Saga, Mutant Massacre, Inferno, etc...)
- Astonishing X-Men (All of it)
- X-Men (v3 is really good)
- Cable ( Both Cable & Deadpool and the Cable solo are good runs)
- X-Force (Start with the Kyle & Yost run, them the Remender run and then the Hopeless run named Cable and the X-Force, all are good)
- X-Factor (If you got the time, all of it, really, if not, the last run is very good)
- Wolverine (Old Man Logan, Weapon X, Origin, Enemy of the State, both Greg Rucka and Jason Aaron's runs are very good as well)
- Storm (World's Apart is awesome)
- Cyclops (The minis are very good, i would also say that if you like sci-fi, his ongoing solo is a very good read)
- Magneto (His ongoing solo is really good)
- First Class (One of my favorities, it's just adventures of the first X-Men team, i liked a lot)
- New X-Men (Morrison was awesome in this run)
Cosmic
- Guardians of the Galaxy (Everything after Annihilation and ending at the Thanos Imperative)
- Nova (The same as above)
- Actually, just read every cosmic thing set afther Annihilation and ending at TI, everything in that era is awesome.
That's all...I bet i may have forgotten something...But these should keep you entertained for a while.