Wow, that is a tough one. It's funny, and I gotta laugh, but I hear so many people tell me that they got all this gear, and then they decide to get the speakers last!!! They get the speakers as a last thought it seems!...which is totally backwards really. The speakers are about 40-50% of the sound of the gear, and should be considered first!!..then adding the gear. Oh well, it's the way it is.
REally, room, taste, listening habits (i.e, sit in one spot, or move around the house, or other listeners), and how loud you play are big factors for sure. If it were my money, and I'm looking at what you bought for amp/preamp, and making a judgment call, I'd look at someithing down the line of some Thiel 1.5's (used at $1000 range) or Thiel 2.2's or 2.3's (used at $1400-$2000) for that tube gear! I've had all in my sytems, and they work great with tubes, and will do reasonable hard rock at harder levels depending*(the 1.5's won't do Metalica that well at volume though). If you could get the 2.3's at around $1800-$2000 used, I'd grab em for those tubes, yes! This is ultra high rez, very clear/neutral sounding w/tubes(better than most by a long way), and do classical, rock, and everything else very well!
Also, this kind of speaker by Thiel will yield you very flexible off axis listening and around the house as well!...which some panel speakers won't allow you to do.
However, you may dig the opposite spectrum like Martin Logans, which you may also like with all kinds of music as well!(*although you must sit infront of them for proper sound..not my cup of tea really). The Logan SL3's can be found used at around you're price range sometimes. All the abover speakers are easy to sell off if you don't like either, alway's some buyers.
My suggetion would be to go to some dealers and listen to the types of sound from these speakers, or others, to get an idea of what you think will do your music right for you. I know alot of audio retailers would shoot me for saying that...but you really won't be getting anything world class or even close for $1500 new at a retail store...for sure!
If you do do this, just be honest and upfront with em, and say you're just listening and gethering ideas, and see if they got any demo's or floor models they want to move or something.
Good luck, it'll be fun though. Ultimately, you