+1 for
Adventure Divers Bali. Liselotte and David are awesome hosts and run a great shop. They also offer accommodation. We stayed elsewhere our first few nights and then with them when we decided to extend our stay. Shoot them an email with any questions and they are happy to help in any way they can.
My wife and I were there in 2014 at the end of March. Our stay inadvertently overlapped with the Nyepi holiday. Nyepi can be an interesting experience, but everyone is "required" to stay indoors for the day, so most tourists head over to the Gilis where it isn't celebrated. I think it takes place at the beginning of March in 2016, but might want to double check.
Also, while in Amed, our favorite place to eat at was
Warung Enak. Small menu, but incredible food.
And you're not too far from Tulamben, in case you want to get a few dives into the USAT Liberty wreck (a night dive there is an other worldly experience). Adventure Divers Bali can take you there, or you can spend a night or two over there since it's an easy shore dive.
Happy to try and answer any other questions about Bali. It's one of my favorite places, though all told I've only spent about a month there.
Cheers,
Mark