basement renovation - ideas?

I posted a question regarding speakers and got tons of great feedback. Thanks to everybody for that. My next question pertains to my complete basement renovation. What considerations should be taken when finishing the basement for optimal sound? The only thing this rookie has considered is 5/8" drywall opposed to something thin! Are there any products out there (without breaking the bank) that will help provide optimal sound quality? The room will be roughly 12x28 with 8 1/2 foot ceilings.

Thanks guys...
There is a very cost effective product if you want to crank up the music and don't want to hear it on the first floor of the house. Green Glue. It comes in large caulk tubes and you put it on between 2 pieces of 5/8" sheetrock. You can certainly use 1/2" but 5/8 is better. Do a search on "green glue" and the website has a tutorial and lots of testimonials. I used it in 2 work applications with noisy tenants (I manage properties) and it worked great in both instances.

I just did a partial renovation of my basement and now I have to do some room treatments as I have a wood burning stove with a large floor to ceiling brick surround in need of severe dampening. The solution so far has been to drape the fireplace surrounding area with a lot of large nylon painters drop cloths when I want to do any serious listening.
Important that you silence all the mechanical equipment. If your heating/cooling system is forced air and the unit is in the basement, extra attention needs to be paid to duct work and equipment mounts of the unit itself. Otherwise, you will hear the noise over the sound of your rig. When I did my room all the walls were double walled in most areas and tripled in the mechanical area. Ceiling was ascoutical, floor built up on 2x4's, covered with carpet.
If you haven't already, also consider running dedicated lines before you put up the drywall. Best to plan where you will be situating your equipment and run dedicated circuits there.Whole lot easier at this stage.

Two thoughts (one practical, one performance) from my last home:

Built ins. CD/LP and equipment storage will make the room more enjoyable to use.

"Built Outs" Cabinets or other structures that protrude from any section of any of the walls will help break up the long, reflective surfaces that contribute to lumpy bass response. I had a sofa built that wrappeed around a Murphy Bed at the listening position. The bed structure protruded from wall about a foot and was covered with absorptive treatment and finished with patterned fabric. Looked great and definitely helped the sound.

Good Luck

There is new acoustical drywall available. I don't know the details, but a Google search should do the trick. It is supposed to provide good acoustic insulation and be deader sounding than regular drywall.
Think of drywall as another bass shakes.
If the room is mainly for sound, consider studs every 12 inches instead of 16", screw and glue 1/2" plywood up first, then put drywall over that with screws and glue. Even using double sheets of drywall will help.
Secondly, decouple the walls from the ceiling above. Putting in a false ceiling will both prevent you from hearing above as well as you shaking the upstairs too badly. You asked, this is an expensive way to do it.
Last suggestion, run all the extra wire you may ever want first. I always pull an extra run of Cat-5 to every outlet just for future use. The cost of the wire is minimal vs having an electrician later.
Double drywall with 1 layer 1/2" AND THE OTHER 5/8" Don't do the same thickness for both layers (diff res. freq.)The green glue sandwiched between layers of dryawall is a good one and will cost less than "acoustical drywall" (80.00/sheet vs. 8.00 for reg) or mass loaded vinyl. I am buildin a basment rehearsal room for myself and that will be much louder than and stereo system. I will construct a room within a room to psyically de-couple the walls and ceiling from the rest of the house. You may ver well do fine with the double drywall and green glue and insulating the walls. Good luck and enjoy your room. There is a good deal of info out there, sometimes too much but this is what I will be doing and I have spent a good deal of time researching it.