I've just noticed that it seems to be a big factor for me in the past few weeks. I find it much more pleasant to play, having the guitar rest on my left leg instead of the right one (which seems to be the norm). This provides me with a tighter grip, thus more accurate playing. My right shoulder/arm also hurts sometimes when playing the guitar on my right leg. It also depends on how I've placed my feet.

Figures it's because I have very long arms (and legs) in comparison to my upper body. Or at least I think so.

You guys notice any difference between stances or positions?

That's because resting it on your left leg gives you the same position as how you would play when standing up. Makes sense to practice like that.

Good point. I also thought about it, because the guitar is more centered to your body that way.

I almost always play standing up because my guitar is an ML shape which is kind of a pain to play sitting down, occasionally, if i can't be bothered to stand i will play sitting down but it usually leads to me knocking the guitar on something because of it's unusual shape.

when I play while sitting, I rest my guitar on my right leg, and when I stand, I usually have my legs spread pretty far so I can get a low center of gravity and headbang in the rhythmic passages, but I'll walk over 2 an Amp/Monitor and put my right foot up there while I solo, idk exactly, but it's easier

I always play guitar with my foot on a stage monitor. ;)
For lessons on this check out any Iron Maiden video.

Sitting with your guitar on you left leg isn't the same as when you stand but it is similar. I always have my guitar on my left leg when sitting, and have my strap nice and short. :P

Ahh, of course it's not the same thing, but it kind of "simulates" it.

I remember when I began playing, I had a real hard time playing standing up. Luckily I got over it after I'd played with my drummer pal a few times.

mine barely reaches my leg, the strap is really short. Having it on the left leg is the "classical" way of playing. That is why there is the grove that your leg fits so well into. It helps having the left leg elevated.

That is precisly why i find RR's damned anoying and why i dont really dig V's, ML's, Razorbacks etc...

I use a type of office chair that is designed in such a way that you are almost kneeling rather than sitting. This means that the guitar hangs on it's strap in the same way as if i was standing. This is great for me as it means all of the angles of playing are the same when practicing sitting down and when playing standing up. I think this is very important personally.

I have a similar chair but I'm a lazy bastard and like to sit in a bad position. It would be more like lying on my back rather than kneeling, haha.

Oh dude I know exactly what you mean, the left leg while having your left foot on a couple textbooks or something, gives you so much reach. I love it. and yeah the shoulder starts to ache if its on the right leg a lot.