Openings:
1) Tonari no Kaibutsu-kun - "Q&A Recital!" by Haruka Tomatsu (This song is so much fun - I especially like the horns [even though they're probably not real])
2) Sukitte Ii na yo - "Friendship" by Ritsuko Okazaki (A sad song, made doubly so by the fact that she is no longer with us)
Endings:
1) Space Brothers ending 2 - "Kokuhaku" by Angela Aki ("I think I love you, I think I do!"
Also I find the combination of a head-over-heels love song and a heavy launch vehicle quite appealing...)
2) Robotics;Notes - "Umikaze no Brave" by fumika (again, very catchy and fun song, and the scenes of Airi exploring Tanegashima go well with the music)