@solitud: I have had this debate with myself as well: why program all day for work, then come home and code for fun? I guess there are two (maybe not very good) reasons: 1) my interest in Arduino programming is high right now; 2) I don't expect to be making Music for quite a while (I'll be mostly irritating the wife/friends/dog, especially at the start).

I don't wanna talk you out of it, I am pretty much in the same boat and even developed a module based on Atmega myself.
Modular synth is a hobby that goes way beyond making music for me. The community chats and never ending optimizations of systems are an integral part of it.
You just have to prioritize at one point since time is sparse and you can not do everything.
So if you wanna do your own sequencer, at least make it kick ass.