Though they are not LPs, I like NFG and STR. NFG is a Nat Gas Dist in the NE with NG E&P. STR is similar but based out of the Rocky Mountain Region.
APL is a Nat Gas Pipeline LP that you may want to look at. They have a unique structure that leverages them to Nat Gas prices. I used to own them, but sold during a big run up in early 2001. If nat gas prices spike again, APL could make another run.