which tubes for which genre ?

What amp do you currently use to drive the Dynaudios? I share the skepticism of some who have posted responses to you -- if you want to rock, I don't see why you're thinking of tubes. I've owned a variety of tube amps and preamps -- Conrad-Johnson, Quicksilver, Primaluna, Audio Research, Eastern Electric, etc. They all had their attractions, but since picking up a Naim Nait 5i integrated a few years ago, I've had no desire to go back to tubes (which can demand a lot of care and feeding, esp the power amps). But I have a small room and mainly listen to jazz and classical, not rock, so your experience may vary. I still think it's worth thinking twice about WHY you want to go tube -- what goal are you trying to achieve? There may be a better means to the end you seek.

Just to follow up on my previous post -- if you are a complete newbie to tubes, and you just want to try them (a perfectly reasonable desire), then you might want to go with an integrated like the Primaluna Prologue 2. It's pretty much plug-and-play, with its auto-bias feature. And it allows you to use various power tubes, so you can compare, for example, KT-88s and EL-34s. You can do a little tube rolling with the small tubes as well to tailor the sound to your liking. I owned the Primaluna for a while and liked it, and unlike some other tube gear I've owned, it always behaved well, never needed fixing.

Another possible combination for you -- a tube preamp and a solid-state power amp. One of my favorite combos from the past was a Conrad-Johnson PV12L tube preamp driving a McCormack DNA-125 power amp -- grace, warmth, and muscle.