I philosophically agree with the three posts so far -- "find speakers you like first," etc. But these folks sound like they are "tube-experienced", and you are a toobie newbee; For that reason, my advice to someone like you, just "getting into it" would be a little different.
Above all, you want your first foray into tubes to be hassle-free. You don't want to have to spend time (at this stage I mean) messing with equipment that won't behave, or that's too high-maintenance for your skill level right now. Therefore, with all due respect for the logic of the previous suggestions, I recommend you focus on the amp first for now.
1. Select 2 or 3 high(er) quality amplifiers from well-known manufacturers (both for support and resale reasons -- this probably won't be your last tube amp ;-) And for now, go with conventional push-pull circuit design (no OTL, SET, etc.)
2. A single chassis (stereo) amp of around 100W/ch should be fine. Many of them can be turned into monoblocks later if, for instance, you bought bigger/different speakers and needed more power.
If you will follow these two suggestions in creating your short list, it will probably include amps from Conrad-Johnson, Cary, BAT, McIntosh, Audio Research. All the conventional 100W/ch amps from these manufacturers are quite capable of driving a wide variety of speakers (even my electrostats) without a fuss. Any more-or-less conventional speaker, like the ones you mention, will perform similarly with all of them. So then it's really a matter of selecting a speaker that sounds beSt to you (IN YOUR HOME IN YOUR SYSTEM!)\
If you will approach the project this way, you can quickly have a really decent tube system that doesn't break the bank yet fits your sonic preferences -- which is what you want right now.
Of the manufacturers I mentioned, probably the McIntosh MC275 (disclaimer: I have one) is the most user friendly AND speaker friendly too. It runs cool, tube bias is factory set and not critical. It puts out a real 95 watts/ch, with balanced circuits, and can be turned into a 180W monoblock at the flip of a switch. It's a really easy tube amp to live with.
Somewhat related. I was pleased that you are focusing on the speaker/amp combo. I believe that should always be the place to start; because IMO, those two elements, taken together, set the sonic character of a system. One can add/subtract different cables, sources, power devices, etc, but they will never override or displace the fundamental "sound" established by the speaker/amp combo.
