Personally, I haven't ever heard either the 50's or 60's. However, my two cents would be that if you go with the 50's, the VP100 and M50 combo might be best. If you go with the 60's the VP150 and M50 combo might be best. Preferably, if there is a way that you can stay away from putting the center channel into an 'enclosed' entertainment unit, that might be your best bet. You might ruin the sound, from either of the center channel models -- and most will tell you the same.
Good luck with your choice, though.
