Best speaker for medium to low power tube amps??


I need advice on speaker selection..they will go in a 19' x 13' x 8' room..my budget is roughly 5k, open to new or used..tube amps roughly 20-70 watts must be the ideal match for these..narrowed my choices to the Merlin VSM-M, Sonus Faber Guerneri, Quad 989 and am open to other suggestions..I'm currently leaning to the Merlin but my only reservation is they are so revealing I will be changing components upstream continually and never finding sonic happiness..thnaks in advance for your responses.
jman
the guarneris are lovely...warm,open,transparent and non-fatiguing sound with excellent midrange. they won't give you deep bass though. they sound great with tubes amps like ARC,Graaf etc. they are not that difficult to drive ...about 87db although with more powerful amps you will get the sense of ease with the way the sound is produced.
The new Audio Physic Virgo would be a nice choice. In a room your size they would like 50w or more I'd imagine. Check out the Immedia site for set-up instructions.
2nd of the Virgo's. Either version. The new ones are better, the old ones are a steal used! BAT VK60 makes a nice match.
I got mine from someone who had been driving them with a 50 wpc tube amp in a room about 12 x 15. He had been very happy with that combination. ( Sold because of low WAF for multiple systems. ) Other sources have also been happy with the Shearwaters ( 88-89 dB/W sensitivity ) combined with tube amps in that power range.

I myself am using a ss Celeste W-4070se ( about 70 wpc ) with my Shearwaters There is gobs of power for my 15 by 22 room.

Another possibility might be Reference 3a. The DeCapos are rated at 92 dB/W. I heard them do very well with Antique Sound Lab 10w tube monoblocs at the 2001 Montreal show.
You might want to consider Revel Performa F30s; I am running them in a 12.5x19.5x8 room with a Jolida SJ502a which puts out ~60Watts/ch (I am using Ei KT90 power tubes; I'm not sure if that increases the power at all, but the amp is rated to deliver 60/ch).

I wanted a speaker that did deep bass as well as a really nice midrange and good detail/air etc. Having auditioned several in the 3-5k price range I settled on the Revels and am very happy I did. I was a little concerned that the amp would not be able to drive them well, but it has no trouble at all (I rarely take the volume past 25%; beyond this the SPLs become quite uncomfortable, though not at all distorted- I just can't listen that loud for any length of time :).

As always, audition before you buy :).