22 to 30ms attack, ratio and threshold to taste, whatever release sounds good.
Then a bit of SPL transient designer to boost attack and sustain just a bit works out great for me.
SSL-type compression does great. The SSL Dynamics and EQ Channel Strip plug-in gave me incredible punch on the snare and kick. If I wasn't using that I'd use a compressor with about 20ms attack, and probably 6dB reduction or so
SPL Attacker is a godsend. A compressor will muffle the attack somewhat, whereas SPL Attacker (or the full version) makes the attack brighter too, which means that when it comes to mastering it still sticks out.
The body of the snare drum is usually around 130-250Hz, boost there and cut on other instruments, providing the snare is properly tuned, otherwise you'll just boost the overtones
One trick I have used before is blend a snare with a nice body/punch in, but lowpass it at like 250 so it's just that - body and punch. Works nice with the natural snare providing the mids and everything.
You dudes that use transient designers - do you insert that before or after the compressor? Or, do you insert the TD on the snare track, and then buss your compression?
SSL comp/EQ(250 hertz area is KEY for punch, and add some around 10k for the high end crack/PSP vintage warmer to make the snare come alive. i blend 3 other samples over the original snare usually. You can use the same processing tips for samples too. Good Luck!
Mike