I was under the impresion that MC specific oils were pretty important. Bob's says no.
The guys on Bob's say not to worry about friction modifiers, but to avoid oil with crazy moly or "StarBurst" fuel-saving oil. Synth is not needed either, just like in cars.

Rotella is supposed to be excellent, both the dino and synth. I'd consider Mobil 5w-40 Truck/SUV too. If I bought a newer bike, I'd use my Havoline Synth 5w-40, which has no moly or even derr German Syntec.
I'm going with an oil I already have, Rotella 30, and 4oz of Auto-Rx that was laying around doing nothing. Supposedly ARX clean the clutchs nicely. The manual for the GSX allows 10w-30, which strait 30 HD diesel is even thicker than, plus I won't be riding very hard. I put in a buttload of V-Power fuel system cleaner too.

fwiw, there IS a Forum just on MC oils at Bob's.<ul><li><a href="http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=postlist&amp;Board=9&amp;page=1">http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=postlist&amp;Board=9&amp;page=1</a</li></ul>

It'll take a bit for the top end to get oil on cold starts.

I ran regular Castrol 10w40 oil in my old '83 Honda CB650SC with no issues.

I ran 5w40 Rotella T in my first VFR, no real issues, but shifting was never quite as smooth as before. With this VFR i have only ran Amsoil 5w40 Motorcycle Oil, changed every 4k miles, shifting stays nice and smooth, even when the bike is hot (where i'd get most of my problems with the Rotella T).

I know from previously that strait 30 is about the same as 15w-40 in cool/warm temps. I won't be doing the cold-start thing either. I'm trying to use 30 too because I have so damn much of it at $1/gallon. I picked up some 15w-40 at the store today to mix in, but said screw it.
Whatever oil I use, I have to run it long enough to make the Auto-Rx effective, about 2000 miles, which is like forever for my purposes. That's where I'm at, but def thanks for the info.

EC oil will make the clutch slip.

I usually start with the dino Rotella and later switch to Mobil 1 15W50. I've used them both in my HawkGT, VFR800, Mille, and 600RR with no problems.