Pro Tools Bomb Factory BF76
The BF76 is an emulation of the Classic 1176 compressor. Recently there has been a flood of 1176 plugin emulations, and probably becasue it's such a great compressor.
It has a fixed threshold, so if you want more compression, turn up the "Input" control. You may need to adjust the "Output" control to compensate.
Attack and Release: The higher the number the faster it responds. So 1 is slow, and 7 is fast. For fun, insert this on a drum bus and try setting the release as fast as possible, then increase the input until you hear some seriously cool compression.
Ratio: I often prefer the 4:1 ratio but you may also like to try the "All In" mode by shift clicking the Ratio buttons.
Snare: Great for a punchy and aggressive snare sound. Increase the input until you get a good amount of "smack" - ignore the meters, don't even look at them :)
Vocal-Rock: Stock settings, adjust input to get the gain reduction to about 6-10dB on the peaks. "I would rather compress a vocal hard to get some personality out. It's like putting a snazzy jacket on a guy when he goes out at night — it adds attitude. And nothing adds attitude more than 1176s." - Chris Lord Alge