active speaker system, ideally child friendly

i am trying to put together an audio system which sounds nice, but is also durable enough so that our 3 1/2 year old can push buttons on it. if he does break something, it can be replaced fairly inexpensively.

we will play CDs (classical, rock, folk, and children's music) and mp3s through our cowon d2 and possibly an ipod at a later date.

my thoughts so far are to move the costs away from the electronics, which can be a good idea anyway for budget systems from what i read, but is especially important with our child consideration. therefore, we could buy some active speakers, possibly a sub, and an NHT PVC Pro and hook them to an inexpensive CD player which plays many formats.

so i would really appreciate your suggestions in terms of the components for this system -- speakers, sub, cd player, cheap receiver instead of NHT PVC Pro. i am happy to buy used where i could get better value. one consideration i forgot to mention earlier, and a reason i am a little concerned about the active speakers, is that the room is fairly large (18' x 18' with a 20' ceiling), but we will not be here for more than a few years so i don't want to design everything around this constraint, just make the system work in this environment.

if i should bail on this idea and just buy a mini cd system, please steer me in that direction also.

some ideas:

1) NHT M-00, S-20 and PVC Pro with a good, cheap CD/DVD player.

2) KRK VXT6 with NHT PVC Pro + cd player. used sub or NHT M-00?

3) used Quad 12L with NHT PVC Pro + cd player. used sub or NHT M-00?

because of the nature of this sytem, i don't want to get really crazy budget wise, but i'm not so constrained that i have to keep it as inexpensive as listed above either so if you see a good fit that costs a little more, please let me know. if you think a passive speaker setup would suit our needs better, please let me know.

thanks very much.

best,
busoni