I am shocked, I thought we'd already had a thread on this
SHOCKING that we didn't
Full Metal Panic was great and had good OP/EDs. Generally I am just a sucker for all of the anime OPs from when I was younger. I have a massive bias so I could probably list every single one I can remember as being a favourite.
Fullmetal Alchemist OP
Red Balloon - Melissa
It's a classic 00s opening with great visuals which didn't give too much away. It might be a bit generic by some standards and the anime has been replaced in a lot of peoples eyes by Brotherhood, but its definitely iconic. For some reason as well i've always been convinced there was a song we sung in primary school assemblies that had a very similar instrumentation/chorus.
https://www.youtube.com/watch?v=dE1fqsapSAc
Steins:Gate ED
Yui Sakakibara - Toki Tsukasadoru Juuni no Meiyaku
I hadn't heard anything about Steins:gate until i went into a HMV and impulse bought the anime on DVD. I watched it all very quickly and the ending had the perfect mood for when the any number of plot reveals happened and you just had to sit there and let it sink in.
I did once the vita version of the VN released play through it then and get mindblown by it as well.. and that has a fantastic soundtrack too.
https://www.youtube.com/watch?v=Se0URL47_Ns
Bakuman ED 3
Tommy Heavenly6 - Monochrome Rainbow
Aside from me loving Tommy Heavenly6, I think the ending song was perfect for the events of the story and the visuals also kept that either hopeful or melancholic tone well.
https://www.youtube.com/watch?v=MslYtaqyNSs
Eden of the East ED
School Food Punishment - Futuristic Imagination
I don't have too much to say on this one, the visuals are great, the song is great and I remember spending probably too long figuring out what the band was called. I actually own the CD for this and their Riff Rain album. Eden of the East is great and definitely overdue for a rewatch, even if you haven't seen it before!
https://www.youtube.com/watch?v=Gb9VOVlwQJs