No matter what anyone else says here (and I know what they'll all say) as you're a fan of Genesis I'm gonna rec my second-favourite band. The rest of you can all suck my d - er thumb. (Cr - ah, crumbs, it's annoying that we have to watch what we say now that there's a kid in the room...)
or for more modern Marillion
I can steer you towards good prog bands if you're interested.
Oh and if you like Marillion try Fish's solo work too.