I'd describe them as Slim fit but not Skinny fit. I'm a cyclist and they are pretty snug in the thigh just above the knee but totally fine for me.
Sky Raider, I just bought some of these. I'm 6'5" and 250lbs. I am also a mountain biker, so I also look for a fuller cut in the seat and thighs. I haven't had Levi's in a while. I'm assuming the 550s are a relaxed fit. I usually take a 38x34 jeans. I Prana I took a 40x34 to be safe. They are super comfortable and quite flattering (or so I'm told). They are cotton (so I keep them out of the dryer) and just enough elastic to make them really functional. A great all around Jean for anything from a casual night out to a fairly aggressive spring or fall hike!! I hoped this helped.