Well, my experience differs somewhat from g4Driver and is more in line with fgs. For me, round/textured polys produce much more spin-- after the first hit. For the first 15 minutes or so, a shaped poly does produce more spin, but I knock the edges off and/or notch shaped polys in the first 15 minutes of hitting. After that, round polys generate more spin for me as a general rule.
That said, the number one determinant of how much spin a string produces for me is the confidence that I have that the ball where land where I want it to land. Shaped poly's (e.g. BH7), for me, almost never have a consistent launch angle and I lose some confidence to hit out (RPM Team is an exception to this.). Textured polys (e.g. Super Smash Spiky) have a more consistent launch angle. I really consider these the same as a round poly because all of the texture is knocked off in the hitting area in about 15 minutes, but these typically don't notch as quickly as a shaped poly. Twisted polys are in between shaped and round/textured in my experience.
Most spin that I have seen for me, though, is a poly-poly hybrid of Black Shark mains, Proline X crosses. My recent experience with Tourna Black Zone tends to make me think it might be a little better as a cross with Black Shark.
Here's my conclusion-- the most spin will be the string that you trust the most to swing out with and maximize your racquet head speed. Racquet head speed is more important than the string.
My current favorites are Black Shark, Super Smash Spiky (17L), Volkl Cyclone 17, RPM Team, and Proline X. All provide similar levels of spin and control for me. I just have to manipulate the tension depending on the string. Once tension is accommodated, the results are very similar, but the feel is different. My overall favorite is Proline X for the duration of a string job. I like RPM Team for the first half of the string job duration over all the others. Second half, not so much.