Tubes 101

I'm very new to tubes. Is there a sonic signature to different tubes? For instance, do Kt-88's have more highs and bass? Do 6550's have better midrange?

It seems like KT-88's, 6550's, EL-34's are the most common, or at least those are the ones that I keep seeing pop up.

I can use KT-88, 6550, KT-90, EL-34, 6L6GC, 7581A, KT66...

In terms of sound, I want it all, and why save $100-$200 on tubes when I'm already this deep in the rabbit hole?

To further complicate things, which brands are better? I'm thinking a matched quad set of Cyro'ed Gold Lion Kt-88's might look pretty sitting in my PrimaLuna Prologue 5....