A thing to remember is that if you want to be twice as loud you'll have to increase power by a factor of ten. To buy a pair of 2x10s and then strangle them with a low power tube amp will simply not get you anywhere. You have to balance the capabilities/needs of your speaker cabinets with the power you give them. I haven't used 30W amps since the Sixties!
That said I do use a full tube pre-amp to drive my power amp.