Sound Library!

My first choice for a sound library is always FMOD. Its fast, easy to use and well documented. However, unless your game is going to be freeware its going to cost you to get a license ($100 for a shareware license, $2000+ for a full commercial license). You get what you pay for though, a top quality commercial sound library.

Or, some people like OpenAL. Its free (as in beer) and pretty good.

Alan

I use DirectSound myself, but that's not cross-platform. I've heard that openAL (completely free like openGL) and FMOD (some sort of scaled pricing deal: the less money you are going to make off your game, the less it costs. Free for freeware, I think.) are both good.

EDIT: Beaten to it.

I also like those APIs so here's my order of precedence and some comments:

FMOD: Best of everything but expensive. Exposes lots of functionalities and extras.
DirectSound: win32 only but does not need license. It has similar features to FMOD.
OpenAL: a joke. While Creative and Apple are putting real money on it, AL1.0 has many weak spots. While it's meant to be portable, many extensions are linux only and that's really bad. The upcoming AL1.1 will probably fix this but it'll take a while.

I played a little with all those APIs and I must say that AL has probably the greatest potential but it's currently untapped.
FMOD would be my API of choice for development because it allows very fast advancement and it's allowed to use it for free provided the product does not go to market (last time I read this). Then, I would switch to another API by wrapping everything up.

I have stumbled in a thing called PortAudio but it didn't conviced me too much.
For cross-platform development, I fear FMOD is the only choice.

I myself use Audiere. While it hasn't been updated for the last year, it works well and is stable. It's not really fancy or anything, but it works for me. It supports all major sound formats, and is licensed under LGPL(so you can use it in commercial products).

http://audiere.sourceforge.net/

props to audiere as well

I think PortAudio aims more at the musical software genre. There's also ASIO, if you're into that -- very portable, but requires a (free as in Beer, I think) license from Steinberg.

Another game-like library is BASS, but I've never used it. Just something to google for if you want to cover all options.

I would suggest OpenAL because it's like OpenGL and I've never had any (major) problems with it. It always has the capability to do what I want.

Also, the ones who are calling it a joke, should take a look at the major games who uses it (do you think they would have picked a lousy sound library?):

AlienFlux (Windows, Linux, Macintosh)
America's Army: Operations (Windows, Linux, Macintosh)
A Tale in the Desert (Macintosh)
Bridge Construction Set (Windows, Linux)
Dark Horizons: Lore (Windows, Linux, Macintosh)
Escape From Monkey Island (Macintosh)
FlightGear (Windows, Unix, Macintosh)
Gish (Windows, Linux, Macintosh)
Harry Potter and the Chamber of Secrets (Windows, Macintosh)
Jedi Knight: Jedi Academy (Windows, Macintosh)
Jedi Knight 2 (Windows, Macintosh)
Marble Blast (Windows, Linux, Macintosh)
MegaCorps Online (Windows, Linux, Macintosh)
Orbz (Windows, Linux, Macintosh)
Postal 2 (Windows)
Shellshock Nam '67 (Windows)
Soldier of Fortune 2 (Windows)
Think Tanks (Windows, Linux, Macintosh)
Unreal 2 (Windows)
Unreal Tournament 2003 (Windows, Linux, Macintosh)
Unreal Tournament 2004 (Windows, Linux, Macintosh)
X-Plane (Windows, Linux, Macintosh)

(taking directly from the official openal.org site)

Every library has its weaknesses and advantages, and OpenAL is certainly not the worst...

I agree. OpenAL worked for the Unreal series, it works for me. It is free, fast 3d sound. That's what I need in a game.