32Ghashes wont be bringing in blocks often at all.
To. OP, try Eligius, they are great, Youd be about 10% of the pool,
Check your math? That'll average almost 3 blocks a week at current difficulty. If that's "not often," then you have a very unusual definition of "often."
I think his problem is that some weeks nothing will come in, other weeks, 6 blocks will come in.
The variance freaks some people out.
Plus with difficulty increases, variance actually costs you because you sometimes don't get anything before the next diff increase. Over a long period this doesn't matter, but in the short term, it can decrease your earnings.