Hi swalto
I'd go with the M3s. I haven't heard the M40s but a reviewer noted that the M3s have more midrange energy than the M40s, while the M40s go lower. The M3s go low enough as stand alone speakers, but they really shine in the midrange. The M22s are more detailed than the M3s but I don't think they're as good a choice without a subwoofer. Although many here prefer the M22s (and most reviewers do as well) my personal preference between these two is the M3.
Good luck with your evolving HT system!
