All righty, I usually don't do this. But I just finished reading this fic and it's absolutely freaking amazing:
Dumbledore's Army and the Year of Darkness In which Neville is a badass and everything is pretty much canon. Essentially, it takes book 7 and follows what all the other characters (you know, all those names Rowling mentions from time to time but never gives personalities to?) spent the year doing while the Golden Trio were doing their thing.
Mmph. Amazing.