Cult Classics for Young Future Audiophile

All of the suggestions above have considerable merit, so I'd like to take a slightly different approach to your post.

Based on my experiences introducing my son (now 34) into the audio hobby, I learned some things that may be useful for you to consider:
1. Kids tend to "crank up" the sound level, despite parental warnings not to abuse the audio system. Hence, you should get equipment that will withstand some abuse.
2. Given the previous statement, the corollary is that it makes sense to buy a higher powered amplifier, since clipping distortion is the fastest way to "fry" a speaker (my son did exactly this...).
3. Buy a reasonably priced power amp that has enough "juice" for the kind of music your kids will listen to. The Hafler DH-200 or DH-220 would be an excellent choice, if that's what you are inclined to get. The Hafler DH-110 preamp would make a good companion unit.
4. Buy speakers that offer good sound quality (to set some standards for the neophyte listener), but is still reasonably rugged, and will play to moderately loud volumes without needing huge amounts of amplifier. For this reason, I would NOT recommend planars or electrostatics for the "newbie".

It's a lot of fun to watch your kid(s) begin to listen to and enjoy properly reproduced music, and it gives the parent a chance to introduce their child to new music (maybe some classical, some blues, some jazz, etc.). I think it's great that you are doing this, and it should be a lot of fun.

After I made my post above, I drove into town for lunch with a buddy, and we got to talking about audio systems for kids. My friend mentioned that he had recently purchased a Rotel RA-02 integrated amp for use in the recreation room, where the system will mainly be used by his pre-teen and early teen kids. He combined the RA-02 with a pair of Krix Equinox speakers, which are fairly efficient, and he said the system works very well.

This conversation made me do some further thinking about this thread, and I want to amend my comments above. Several points which seem pertinent are:
1. The system needs to address the listening habits of the prospective user, not the seasoned audiophile, so keep your kids needs in mind. Floorstander speakers may not be the best choice, even though I like the idea of something like Vandersteen 1's. A "bookshelf" speaker is likely to be more practical, and easier to drive since it will have less low frequency output.
2. One of the newer models of inexpensive integrated amps might be a good alternative to "classic" separates. It's simpler to use, easier to set up, and if it is combined with efficient speakers it can provide a good taste of good sound. The Rotel RA-02 has gotten very good reviews, it provides 40 wpc, and it is not very expensive. Audio Advisor also sells several other good integrated amps: the Cambridge A500 (65 wpc) for $400, or its smaller brother, the A300 (50 wpc) for $249.
3. An efficient bookshelf speaker (90 db or better) should provide adequate volume, assuming the system will be used in the youngster's bedroom. There are some good choices for lower-cost speakers that should fill the bill:
a. Krix Equinox speakers can be purchased used for $300-350;
b. Wharfedale Diamond 8.1 or 8.2's, which Audio Advisor sells for $200 and $300, respectively;
c. B&W 303's, which have gotten very good reviews, are fairly efficient, and sell for around $300.

Hope all of these posts give you some good food for thought.