Tough call. My first thought would be "no" since the biggest difference seems to be in the frequency range your sub will cover anyways.
My second thought is "yes" in case you end up deciding in the future to use them for 2.0 listening without a sub... although the M80v4 seems to do a great job there anyways.
My third thought would be "oh crap, I don't know what to do" so I would probably decide based on height -- I'm fairly tall and I end up raising most of my furniture a few inches so M60/M80 speakers need to be tilted up a bit unless I'm sitting far away while M100's would be just the right height.
It's probably fair to say that the non-HP M80s are all you need if you have a sub, but there's no way I could resist the HP option even so.
So M80HP's unless you're really tall, in which case M100's
EDIT - speaking of loops, the loop I would get stuck in is :
- all I need are M80s
- it's only $500 more for M80HP's, duh !!
- it's only $500 more for M100's, duh !!
- oh geez, I'm up $1000 already
- repeat
Eventually I would get yelled at and told to "just buy the damn M100's and stop agonizing".
