Help me put a system together for under $1k.

What does your system consist of? If you dont mind.If you and your son do share similar tastes maybe people here could make suggestions of components that share similar characteristics, or even comparable components at a reduced price. its just a thought

Does he already have a computer?

At work my Apple G5 is connected to a Swan M20L satellite/subwoofer set up that sounds decently good using iTunes as my music source. Swan speakers are known for being "midrange first" in design, so that ultimate extension at both is slightly sacrificed so a full-bodied midrange comes through very nicely. The sound is natural and dynamic. The subwoofer has a built-in amplifier for the sub and has stereo outs that feed the satellites.

At work my friend set up a dedicated computer/music server which can play 63 continuous days of songs through iTunes without repeating a single one. Plus, a computer running iTunes gives your son the ability to explore new music genres via the online iTunes Store.

I bought my Swan sat/sub unit on Ebay for about $170. Used in conjunction with an existing computer or adding an iPod for $300-400 would make for an affordable, musical system that won't have the family running for cover every time 50 Cent starts bumpin' in the Candy Shop.

Hi
I agree with the posts above saying that dont decide for him, its not a very good start point.You could do a speaker an amplifier list(to reduce the spectrum) and take him to audition. So he can decide by himself. The process will be fun and will let you know what he really wants or needs.

Again, I am looking for a smooth sounding system without bloated bass, harsh highs or very prominent or "forward" midrange.

Keep in mind that it's your choice of speakers, more than anything else, that will govern this. You can buy awfully cheap electronics today that entail relatively little sonic compromise, so budget according. As for speakers, to each his own, but be sure to include in your comparisons one or more of the following brands: Energy, Paradigm, PSB, Infinity, JBL. These are all companies with a very particular approach to good sound (and some solid research behind it) that makes a good standard against which to judge the rest of the market, especially in the budget category.

I'll second the Technics turntable recommendation above. It's not high-end by any means (and definitely upgrade the cartridge), but it's a p-mount unit, which means it'll be easy to set up (good for a kid), and it won't trash his LPs--so he'll still have them to listen to when and if he decides to upgrade.

Finally, as the guy who started the "ask your son" trope, let me say that it wasn't my intention to give you a hard time. It's just that we regularly see posts about what to buy/recommend for a "friend," which turns out to be an exercise in foisting one's own hobby/priorities on somebody else. I meant to warn you away from that, though your follow-up post suggests you weren't falling into that trap. My apologies for any suggestion otherwise.

NAD L 40, JM Labs 705, you know the rest.