there is a time and place for speed, your right.. but it should be tantalising, short, and sweet.... having said that i have used tapping for rythem, which actually sounded really cool, but the timing was a pain in the back side... but it shouldn't be predictable or cheeeeeeeeeeesy....
Personally I like hearing a song with a decent solo that FITS, like the solo on "i wanna be sedated" wich is one note... which works well, and the solo on "all along the watch tower" (the one that goes slide -wah - panning) which is very cool that FITS with the rest of the song... too many times i hear a song with a solo wich feels out of place (like "undone the sweater song" by weezer)...