[Snarf]

http://www.megaupload.com/?d=57X5FOOF
Rar includes two wav files; the codec from mgs and Navi's HEY from loz ocarina of time.
These replace the default steam message noise. I don't like the default wav and I find these to be far more noticeable.
Installation Instructions:
Extract the sound you want
rename it to message.wav
dump it into steam/friends
right click the file, click properties change it to read only
Click apply, close the window, enjoy.

Feel free to make requests for additional sounds, it's pretty damn easy to make these.

[Adder]

http://www.youtube.com/watch?v=cvkBvzpbB...re=related

2:12 and 2:34 would both probably be pretty good, although I will admit I won't use it and I really don't care if you do it, Just throwing it out as a suggestion in case you/others might like it.

[ToInfinityAndBeyond]

I love how most people change it to something LESS annoying.