Tor takes too much RAM

[Ben Wilhelm]

# free
              total       used       free     shared    buffers     cached
Mem:         98520      96772       1748          0       2220       5848
-/+ buffers/cache:      88704       9816
Swap:        65528      58480       7048
# killall tor
# free
              total       used       free     shared    buffers     cached
Mem:         98520      41464      57056          0        644      10356
-/+ buffers/cache:      30464      68056
Swap:        65528      22496      43032

I'd love to keep it running, but when it's singlehandedly chewing up 
more than half of my system's RAM, it just isn't going to happen. Any 
suggestions on this? Are there config options I can tweak to make it a 
little less RAM-hungry, or is it just intrinsically a memory gobbler?

-Ben