Fitting a bike

Was going through some old posts and read a post where someone pointed out the fact that careful attention should be payed to how the bike fits you, due to getting body fatigue from riding. Now having a history with other machines like these, mainly snowmobiels I know that SOME fatigue is normal, but there are limits and a point when it jsut becomes dangerous.

So I was looking to get some advice to how to fit the bike to my size/weight. Should I just sit on some and test drive a few to see how they feel or should I be looking more indepth?

I'm 6'1, 180lbs, not really lanky, but have long legs and pretty long arms.

It's a matter of personal preference and taking the time to sit on different machines to get a feel for them. I'm 5'10" so I can say that some bikes you sit on will definately NOT be comfortable. Others, especially while you learn, are much more reasonable. But realize that if something doesn't fit you well for a few minutes, it will HURT after a few hours.