Scan-Speak cones has 1 of the most sweetest midrange drivers out there and even tho I've never heard the Sapphires, I have Scan-Speak drivers in my Lorelei's and they are truely captivating. That and the fact I trust Lonewolf who has heard them makes for an easy choice to me.
Oh yeah, I do have the Force XL and you won't be disappointed when you start feeling the vibrations in those bass ladened movies.

Are you planning on rear speakers or are going to just half step your home theater?

A center channel speaker is a must have item for correct direction and motion of the sound. Now it's no biggie if the center's different from your mains but today, there's a lot of Dolby Digital and DTS concerts available, my DirecTv HD has concerts in Dolby Digital each and every weekend and to properly enjoy this, ideally you'd have 5/6/7 speakers that were all the same. Anyways, I'd recommend that
if you don't plan on rears (big mistake), I would try and get Mike to sell you 3 Sapphires for your front line speakers. You'll have correct tonal balance and even tho isn't not necessary for movies, it's a must for music. Even if you're only a 2-channel music fan, you'd be shorting yourself
bigtime for those music shows in true digital surround, aka 5.1/6.1/7.1 with
each speaker having it's own true individual sound. 2-channel doesn't cut it when you're talking about home theater DTS/Dolby Digital recorded music.
Something to think about and I know what I'm talking about from experience with my own home theater system. Ideally, 3 sets of Sapphires and Force XL for a mind blowing 6.1 system. With a good 6.1 Dolby Pro Logic 2x (that's coded surround, unlike Dolby Digital), it'll rival 2 channel head to head. That's
TOTALLY the bias in me talking so YMMV. aa
Good luck with your decision.

Cheers,
Robin