I have an M&K inwall system. A pair of SW-95s are my mains and a pair of SW-85s are my surrounds. I have the S150 as my center speaker which sits in the HT armoire. All speakers are powered by Outlaw amps (a 755 and a pair of M200s). I couldn't be more pleased with the results of this system. If you're in it for HT, the M&Ks are extremely accurate. Auditioning an M&K regular speaker system should give you a fair idea of what the inwalls sound like.

I'd also suggest you shy away from inwall subs. The placement of the sub is quite critical and you shouldn't limit your options despite having kids. My kids (and wife) were trained at a very early age not to mess with daddy's subwoofers.