Well, I've taken a new philosophy with my DM'ing. In 2nd edition, there were so many creatures that had "save or die" effects. I didn't like those. I stayed away from those creatures. I never wanted PCs to just flat out die with a bad dice roll. But, in 3rd edition, they've made it so much easier, and much more balanced. Now, poisons just suck up tons of ability score damage, and level drains are a little more repairable, and a little easier to save against.
I've decided that I'm going to run the monsters as if I _were_ the monster, and I was trying to survive. Hence, I'm coming out with all their big guns first and foremost, having a detailed tactical strategy outlined, including a backout plan. Like, for a Slaad encounter coming up, I have a pair of Blue Slaad using their Hold Person abilities every other round to try to disable them, and a Green Slaad will remain hidden in the shadows using his Chaos Hammer effect every round to soften up PCs. When he is discovered, he will likely flee.
In short, my players aren't going to know what hit them. I've already killed the sorcerer, and while he was upset at the time, he knows that he has no one to blame but himself. Hey, it's not my fault an Aboleth dominated him as he wandered -alone- in a submerged section of dungeon.
Also, in 2nd edition, I used to use a DM screen, and fudged lots of dice rolls. I'm not doing that anymore, and I'm just going to let the dice fall where they may!
It's liberating!