i have a membership with Sam's Club, and hell i use it mostly for the gas, its always generally cheaper then any place around for me. Plus when you do need certain things in bulk its always a good buy.

My view is, since i worked for Sam's for over a year and know someone who worked for costco at the same time...

Sam's = better deals on dry grocery and generally frozen/produce style stuff
Costco = better deals on hard-lines stuff and electronics!