It's Boston, for me. It's hard for me to pick any one band above all others, but Boston certainly qualifies when I try to think of one. Of course, it doesn't hurt that I grew up listening to Boston.
![Razz :P](./images/smilies/icon_razz.gif)
Here're a few examples from these bands, for those who might not be familiar with one band and/or the other:
Chicago 1
Chicago 2
Chicago 3
Boston 1
Boston 2
Boston 3