@phreedom76do you plan on putting a bookshelf (or RC-LCR) on speaker stands? If so, the footprint of them vs a tower speaker is basically the same. Your kids will be just as likely to knock them over as they would a tower. FYI - I have two crazy boys, ages 3 and 1 and they have not knocked over my tower speakers(knocking on wood).
I don't think you should eliminate speakers from your list based on how they sound while using an amp that you don't intend on usingand especially the Lepai. I've heard that's a nice little amp to give you some decent sound, but I doubt it would hold a candle to the HK you are looking at or another comparable receiver. And regarding your receiverI would try to get one with bass management/Audyssey (like Jim Z said) if you plan on getting a sub.
I will not tell you to forget about Boston Acoustics.http://www.vanns.com/shop/servlet/it..._a_7c542469405http://www.soundstage.com/revequip/energy_rc10.htm
Seriously though, I own Energy products and have RC-10s, RC-70s and a RC-LCR. I started with a pair of RC-10s as front L/R and thought they were okay speakers in that role, but certainly felt they were lacking with certain types of music. The three-way design of the LCR will give you better clarity with voices and better bass response vs the RC-10s. I think you'd still want a sub if you went with the LCRs though. IMO, stepping up to the RC-70 will give you the clarity of the LCRs and much better bass response. I think if you went with 2 RC-70s you might not even need a sub for your 80% music listening. You'd be missing the deep bass in movies, but in an apartment setting, I'm not sure you'd want to be shaking the walls and floors too much anyway.
If you are set on bookshelf-type speakers and can afford them, I would recommend going with the LCRs or E-60s that have been mentioned, paired with a good sub. If you plan on putting them on speaker stands, I wouldn't rule out going with towers and think you should explore those options.