I am a Christian. I am a pipe smoker. I am a sailor. I am a reader. I am a struggling artist/musician. I am...
I'd say that for me, my life style is just the sum of my hobbies and interests - it's the sum of all I do.
I really like the way you put that, Phillip. I am kind of in the same boat. Pipe smoking is probably more of a hobby for me (along with collecting, refurbishing and now, pipe making [I'm beginning to attempt that, at least]), but I consider it as part of a lifestyle that I would say is broader than any one thing.
For lack of a better phrase, I would say that lifestyle could be summed up as, "the gentlemanly pursuits." These (for me) include (but are not limited to): politeness, good manners, having integrity (especially, when I give my word), a literary practice (meaning, I try to read a book once in awhile--so as to stay open minded about the world, and people), optimism, artistic pursuits (which can mean anything from looking at a painting to creating something with my hands--whether I think it's "good" or not), a good work ethic, a healthy suspicion of my government (and the knowledge that nothing they can do, short of imprisoning me, really affects my day to day happiness--unless I let it), curiosity about the world (and its people), and practicing the golden rule...among other things.
I say this, not to distinguish myself, as I see that many of my pipe smoking brethren practice these "pursuits," but just to point out that many of us have these traits in common. The fact that OTD even asked the question displays that curiosity about the mysteries of pipe smoking, whether you see it as a hobby or a lifestyle.
I guess what I'm trying to say is (which many here have already said more eloquently), that's a hard question to answer. Nonetheless, it's a great question to ask. But, I think Simnett's tobacconist really hit the nail on the head...
Cigarettes are an addiction. Cigars are a hobby. Pipes are a religion.
I'm off to go practice my religion...