Since somebody asked earlier - as far as I know, lane splitting is not legal in NY. Still, I've been doing it as long as I've been riding, and have never gotten a ticket for it. But I don't lane split past cops, and I don't cruise through stationary traffic at 60.
To everybody who says that (safe and reasonable) lane splitting is bad for the image of motorcyclists: bulls**t. The more people lane split the better, because then cagers get used to it.
If every bike sits in stop-and-go traffic waiting to get squashed, and only a few people lane split, the lane splitters look reckless, sure. But if everybody does it, every time, cagers' tiny reptile brains make the connection, "well, that's just what bikes do".
Lane splitting is more accepted in California by cagers not because it's legal, but because everybody does it! Do you really think that the average genius behind the wheel in California sees a bike lane splitting and thinks to himself, "oh, it's OK that he's doing that because it's legal"?
Most drivers couldn't answer basic questions about traffic laws if their gas prices depended on it, so I don't believe for a second that the average cager knows what's legal for motorcycles where.
The only way for lane splitting to become accepted (tacitly if not legally) is for everyone to actually do it. In and around NYC most bikes lane split, and I've never had a problem with drivers getting noticeably huffy about it. On admittedly anecdotal evidence, in places where people don't lane split as often, drivers get very belligerent, try to block bikes from going past them, even open doors, etc.
So lane split, it's good for you. Just do it safely and reasonably. I certainly agree that the guys racing through traffic, as described by the original poster, are complete idiots.