EDIT: Sorry for going off on a wild tangent here, this post isn't so much about sampling as it is about the whole "music isn't free" mentality...
Sample everything and anything, twist it around, recontextualize it, whatever. If someone goes after you for copyright infringement, sample that too and use it in your next song. If they come to your house, pull a Waco and go down in a blaze of glory...
Music will always be here because people make music out of a passion to express themselves. And that requires no payment. IMO the best thing that could happen to music as an artform right now is the complete abolishment of all intellectual property laws. It will kill the recording industry of course, but that is something that I think A) Is already happening anyways and B) NEEDS to happen.
"But oh noes, how am I supposed to make a living as a composer if we do away with royalties and such?" My answer to that would be "why is it automatically assumed that just because you wrote a song people like you should get tons of money for it and be financially secure for the rest of my life?" Why is that the done deal?
The only reason the current arrangement came about was due to the limitations of hardware distribution of audio(wax cylinders, vinyl, CD´s) - in the larger scheme of things, the recording industry in it's current form will be only a blip on the historical radar, here and gone in the space of a few short decades.
There are few things I like more in music than to hear a snippet from a song I either hated or loved sampled and recycled into something completely different. Losing that is not worth keeping an industry already on life support alive for a few years more.
I think the digital age has created a new sense of entitlement...people have devalued music itself - they expect it for free...it's no surprise that artists also expect to take something they hear that they can easily copy or sample and create a derivative work and expect that it's free...
I think music should be free, especially today when the internet and file sharing have transformed music from a private good to a public good(if you don't understand the distinction, google the terms as they are used in economics)
Live performances will always be paid for since they are inherently private goods. So musicians are here to stay no matter what. So are engineers, roadies, techs, lighting and video peeps and basically anyone involved in the creative side of music. If you got chops, you got a job.
It's the bean counters that have been rendered irrelevant for the most part, which is why the publishing giants are going after copyright infringers so hard, it's their jobs that are on the line....
Anyways, sampling anything from a hit single to enviromental sounds is IMO as legitimate a way of making music as any other. It's just as easy to compose bland, unoriginal guitar riffs as it is to compose an unoriginal song based around samples.
Here's looking at you kid...