the differnces in tone are huge between the two, but the real difference to me is in comfort. les pauls have a thin neck versus the thicker neck of most fenders so if you have fat hands the fenders going to fell a little better until you hit the upper frets and the set neck on most (good) les pauls takes over.
most les pauls have a flatter neck cut until about the 12th fret and a big radius (i think its over 12 inches) while most fenders have a classic 'C' shaped neck and small radius (i think its around 7 1/2 inch). (do your own home work on the radius for the exact guitars you might buy to be sure). a big radius makes playing lead easier while small makes chords easier.
the other big diference is in the body cuts. i can sit in horrible playing position(almost laying down on my bed) with my fender and watch tv while i play and feel comfortable. but if i try that with a les paul the top edge of the body cuts into my ribs and i can never seem to get the neck at just the right angle. standing up it makes no real difference between the two.
They say the END is near, but I'm Tired of waiting.