Inexpensive pair of bookshelf speakers.

A bunch of good suggestions here. Of course, it really comes down to personal preference. But if I were you, I'd want to listen to the Cambridge Audio Aero 2. I haven't had the chance yet, but the CA S30 is a terrific little speaker, and what I've read about the Aeros is very interesting ...

Good one Mapman, funny!
Epic 2
Studio 20s
Q300
Rega RS1
Silverline Minuets
Totem Dreamcatchers
B&W685

All in the price range but which one to chose for the type of music I listen to?
Maybe others?

I still like the Dreamcatchers just for the fact that I loved the Model 1s and I can buy new ones for around $500.00

However, how good are they?

One of the very best book shelf speakers I ever heard is the Infinity RS-1 speakers, from 1996 or 1997, I have a pair I bought from a yard sale back in 2012, I remembered they got Editors Budget Best choice for the year in stereophile magazine way back then, so I bought them, confirmed the review and award from stereophile and fired them up, they have a tiny woofer, 4 1/2 inches, two way speaker, these speakers are incredibly heavy and well built, solid as a rock, the sound?, I was in awe, they have an extemly timberal sound with great clarity and detail, the bass is very impressive for such a small woofer to say the least, I will never sale these!, what a deal, $20.00 !!!, all that I have said may sound dis-believable, Really, These speakers are that good, of course this was before infinity went down market!

Given what you're looking for I'd reiterate my recommendation of the Minuets and add Joseph Audio RM7 and Ref 3A de Capos if you can find them used in your price range. I know your tube amp is relatively powerful, but I'd still be leery of speakers that drop to 4 Ohms or below (wouldn't be as concerned about sensitivity so much), and all three of these speakers are relatively tube friendly designs. Highly doubt you'd be disappointed by any of these, and best of luck in whatever you ultimately choose.

Thanks Soix,
Just got an offer to buy a pair of Model 1s at $650.00.
Trying to bring it down to $600.00.
Keeping my fingers crossed.

I've heard great things about the Minuets but I have never auditioned a pair. Definitely in my price range if I buy used.