Dayton Audio Sub 80 is excellent for its price ($75).
http/www.parts-express.com/pe/showdetl.cfm?Partnumber=300-631
You are down to $574.
As far as speakers go, you cant find anything that beats the value of the Take 5s at this price. You will thank me later, but satellites...are just terrible.
The only satellites that are worth considering at your price range is the Klipsch Quintets, and for 5 speakers I believe the lowest price is $250...above the Take 5s. The Take 5s weigh slightly less than 3lbs. You should have no problem wall mounting or fitting them on your desk.
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The question is, HOW much do you love music? You don't get much value getting 5 speakers + sub if your main goal is music. Music is predominantly stereo (2 channel).
If your MAIN goal is music, 2 bookshelves+amp/receiver or a pair of powered monitors would be your best bet.
In fact, unless you have at least $300 to put down on a sub like that STF-1 (or less used), I would ditch the idea of a sub completely, since anything below will largely have trouble meshing with your music. A GOOD subwoofer you do not HEAR, otherwise something is wrong, because the sound recording has no bass channel. It should be invisible and mesh with the main speakers. If you can tell which direction the bass is coming from, chances are your subwoofer is just not very good. This is because true bass (below 80hz) is non-directional. If you can tell where the sub is, it is distorting at harmonic frequencies well above 80hz, which is why you can tell where the bass is coming from. The multimedia pc subwoofers out there sound like someone blowing through a toilet paper tube.
If you want to go powered monitor route, the Swan M200s are probably the best PC speakers ever made.
http/www.theaudioinsider.com/product_info.php?products_id=80
If you are really a die hard music fan, this is my #1 recommendation:
1) Buy a pair of bookshelves
2) Buy a receiver
3) Save money for more speakers + sub
I have owned the Altec Lansing ATP4s, MX5020s, Logitech Z-680s before moving to bookshelves + subwoofer. The difference is night and day and you hear details in the music you never realize were there. The room fills with sound because bookshelves disperse sounds extremely well, whereas those tiny satellites beam sound like lasers.
I actually ended up ditching the subwoofer because I found there was a little too much bass from "small room bass reinforcement". I'm currently running a pair of high end bookshelf speakers with a receiver and the sound is just...heavenly.
Let me know if this is something you'd like and I'll shoot some suggestions over. Otherwise, I don't believe you can find a better deal than the Take 5s for surround at this price range.