Depends where you are as far as your chip stack is concerned.
If your doing quite well (say M=40+) now is a good time to knock out a few people who were clinging to the thought of making the money, sit back wait for your hands and be aggresive to the smaller stacks on the table, chances are they'll donk their chips off to you and be happy with double the buy-in.
If your around average (M = 15-30) you should tighten up and make yourself scarce while the short stacks take their shots and the big stacks bully the table a little, when things calm down a little you'll be seen as tight then you have the chance to loosen up a little as the table will respect your bets.
And if your getting low (M=10) there's no point being completly desperate you still have enough chips for a few orbits, but you are looking to play your strong hands super aggresive and trying to keep your hands out of the cheap multi way pots as you will bleed what little chips you have left all over the table playing in these hands with your chipstack.
Of course all three of the above are a guide and in the perfect world would be law (i guess .).
I say play to the table, if everyones as tight as a fishes butt and your short stacked, take pot shots, if you've got alot of chips and your card-dead or the middle stacks are playing loose just sit on your chips, meh .