Walter E Williams is also my favorite, but because he doesn't get used as much as the others.
The sad part is mark belling is usually much better doing the local show than he is filling in for rush. As a sub he's more restrained and careful. With his own show he'll go off on tangents and get a little weird, but that's what makes him interesting to listen to.
I'm not familiar with the guy on now, but I heard some yesterday and got the sense he was swinging a little above his weight.
Roger Hedgecock, though, annoys the sh*t outta me.
But I listen anyway, because the only alternative is Springer or Franken.
I think it's because the others are actually talk show hosts so their always ready to go whereas Williams is a Professor at George Mason Univ. and probably is busy doing that and writing great columns. :)