plus don't forget that tube amps are (insert correct and generic number, such as 3 or 4, here) times louder than solid state amps. My 200W Randall RG200G3 (solid state) was loud, but I had to crank it to get anywhere near where my 120W 5150-II is (although to be fair, it did only have 2 speakers rather than the 4 I have now!).
I would guestimate that a 60W Fireball would keep up EASILY in the band mix - especially if you're putting it through a 4 x 12" cab of high efficiency speakers, as I mentioned above: 60W of tube power is a LOT :)
Also don't get misled into thinking that, all other things being equal, 60W is half as loud as 120W. It isn't, and besides, all other things are rarely equal.
My advice is still to go for the 5150-II (6505+), though, but I'm biased because I want to have my amp's children.
Roo