old chicago is ok, but they have sucked since 1978.
That was I believe the year guitarist and front man Terry Kath ate a bullet.
If you like 25 or 6 to 4 stick with the early albums. There is not a lot of stuff that sounds just like that song. I hear the early stuff sounds really good when you're stoned also
You might also like Bread and Three Dog Night.
I saw Three Dog Night in concert a few years ago. The never sounded better.