I like BitMinter they don't draw pretty graphs but they give you the raw numbers as they roll in: worker effort, your shares, solved blocks, transactions, much like a bank statement would.
Most importantly I can take my payout daily reducing my risk to pool hack/failure!
I've used them for years and feel they treat me fairly.
Like others said, for the sake of the network, DONT join the biggest pool!
http://www.bitcoincharts.com/bitcoin/ (scroll down for pie chart)