How many tube watts for Vandersteen 2's?

I used a Audio Research Classic 60 with my 2Ci a few years back with absolutely no problems. Given the size of your room any tube amp over 35 watts with a good power supply should work. Obviously more is better, but it's a starting point if funds are an issue.

Believe it or not, the best I've heard Vandersteen 2s (and I've heard them a lot) was with a 35 watt Music Reference RM10 at John Rutan's Audio Connection, when he and I were hanging out with one of his salesmen one afternoon several years ago.

That was simply one of those few and fleeting magical moments we all experience in audiophilia. Nothing was lacking. Even the low end, which was incredibly fast (normally, one the Vandersteen's real weak points), and possessed true snap. Ahhhhhhhhhhhhh, I close my eyes and can hear it all over again - Dick Dale's surf guitar has never sounded finer to me.

Also heard the speakers with a pair of Quicksilver monos when I was last there in November, and though good, didn't come anywhere close to the aforementioned experience.

I also heard the Vandy's at AudioConnection in Verona played by John Rutan! One of the best sounds in a dealer showroom I have EVER heard. Played a Terry Evans CD that just sounded so alive.

I used one of these 25 wpc in a room bigger than yours:

http://archive.anthemav.com/OldSitev1/review/int-1.html

It's really more important that you have some current behind those watts. For example, you could use a pair of Dyna MKIII's but you won't like the way the bottom end sounds. Sixty tube watts is sufficient if you don't play your music loud. Just use a tube amp that has some decent energy storage. Most of the ARC amps do. Roger's amps do as well i.e. RAM Labs/ Music Reference. Just remember, current controls the bottom end on dynamic speakers.