I used to have my VP150 sitting on top of my television, and had it that way for a long time.
Recently, I got a new t.v. and stand, and it is now sitting underneath the T.V. on my stand. It's tilted to aim directly at my listening position, and pulled out enough so that the front of the speaker is right at the edge of my stand- so there is nothing obstructing the sound to the sides or above/below it. It has room behind it, too, though I don't know if that matters much since it isn't ported- but the fact remains that it can "breath" and doesn't sound like it's inhibited in any way by shelving/objects around it.
I think that as long as you make sure it isn't pushed back too far in your cabinet, and the drivers have unubstructed room around them, you'll be happy.
I like how my setup is now, because before the center channel speaker (especially with it being so relatively big), drew a lot of attention to itself up ontop of the t.v. Now my setup is more sleak and the center speaker blends in with the rest of my setup better.
