Instead of rotating, I use CGminer/BFGMiner pool balance feature. It is a great way of decreasing variance.

I used 4 pools in the past namely BTCGuild, Bitminter, Eclipse, and MtRed. Sometimes replace one with OzCoin (be great if workers can be configured individually).

With BTCGuild hash rate going up exponentially, Bitminter connection problems, and MtRed shutting down; I am now currently using Eclipse and Itzod.

2 workers on Eclipse (1 configured as DGM and 1 as PPS) and Itzod replaced MtRed.