EQ is a really touchy subject; a lot of engineers avoid it like the plague. Quite simply, you can ruin a really good recording if you EQ something wrong. You'd be surprised at how a little bit of EQ gone wrong can change the whole perception of your mix!
For a really good kick and snare sound, we need to do a little bit of EQ to get things to sparkle in the right places. Make sure you've un-soloed the tracks, so you're listening to the whole mix together. Any changes you make in EQ on a particular track should be listened to against the whole recording.
Place an EQ plug-in on both the kick and snare -- I really like Digidesign's new EQ III plug-in. For the kick, add a tiny bit of low-end, and then pull down the mid-low quite a bit. You'll need to adjust the "Q" setting to make it less wide. Then, bring up the mid-highs just a touch, and you'll end up with a warm, snappy-sounding kick. For the snare, I prefer to bring a little bit of mid-highs up, and kill most everything below 80 Hz, and sometimes, depending on how much of everything else I'm picking up, I also kill some of the highs as well. Aside from that, play with the curve; your ears (and song) may benefit from some added "air" on other tracks around 8-10khz.
I tend not to use EQ on most everything else on the drum kit, with one exception: on both the overheads and the high-hat, I tend to remove everything below 100 Hz, mainly because cymbals don't project anything in that aural range.
Now, let's look at one final step -- making sure everything is even.