Gas prices are bad everywhere right now. I think the M54 engine is underpowered for the truck. I have an e39 with the M54 engine, and it's OK. In stop and go traffic, mpg isn't brilliant. I read reviews in C&D and mpg isn't great in hybrids either in stop and go traffic, but I am not considering hybrids. rather a diesel, but diesel prices aren't cheap either, it's not available at every gas pump and mpg suffers in stop and go traffic also, just as much as a gas engine.
I want something that's also fun to drive, and a 4.4 engine and up for the e53 fits the bill.