When MC2 first came out, I believe it was Spider-Girl, A Next, and J2. Both A Next and J2 lasted 12 issues. Along with that, they released Fantastic Five and Wild Thing, which only went to 5 issues. That kind of killed things for MC2, except Spider-Girl. A few miniseries have come out that help explain certain characters in Spider-Girl, most notably The Buzz and Darkdevil. (I think each was 3 issues long.)
(Wow, I just went onto Wikipedia to see if I missed anything, and they pretty much have what I said.)
Anyway, you probably know about Last Hero Standing and Last Planet Standing, both two very good miniseries. I would recommend the books in this order:
1)Spider-Girl (original series)
2)Last Hero Standing
3)Last Planet Standing
4)Avengers Next
5)A Next
6)Darkdevil
7)Amazing Spider-Girl (not enjoying new series as much as previous for some reason)
8)J2
9)The Buzz
10)Wild Thing