While audiophiles might tell you tube amps are "better quality" the actual reality is that they can be extremely "hit or miss or miss or miss". SETs in particular are a general disaster 99% of the time, and even general tube amps can really hurt the sound quality of most speakers, especially anything with impedance fluctuations and average sensitivity.
We really need to know more about your tube amps, because they will likely be your number one system bottleneck.
For example, some very fine speakers in the sub-$5000 range include Revel F52s (you should be able to get them, just barely. They're a notable step up from the F32s. Studios are likely out of your price range, even used), Salk HT2-TLs, Philharmonic 3, and Pioneer S-3EX. I consider B&W speakers to be all hype, with no performance to back it up. Again, though even all of the above excellent speakers may not truly be tube friendly. If you're willing to go up to $6500, consider these:
http://www.audiokinesis.com/product_ak_planetarium-alpha.html
In my opinion, even a $5000 budget will still benefit from adding multiple subwoofers. The bottom octaves are truly the most difficult to reproduce, plain and simple. If you focus on getting everything above subwoofer range handled by other speakers, you will reap the rewards of multiple subwoofer approach. Another extremely tube friendly, and very high quality speaker is the Geddes Abbey:
http://www.gedlee.com/abbey.htm
But it requires the multi-sub approach to get the best bass. You will find no shortage of praise for the geddes speakers on the internet. They're controlled directivity designs with a wide sweet spot, powerful dynamics, and no shortage of details. They're also very room/amp independant.
Now regarding electrostats/planars... I think they've got some huge positives and some large negatives, like other speakers. The positives include that much of the side wall reflections are virtually eliminated over much of the frequency range, leading to a dominant direct sound (and less need for treatments muddying up later reflections. Also, the rear wave can seriously add depth to the soundstage. Finally, these types of drivers tend to have extremely good phase response. What are the negatives? The upper mid and higher frequencies are "beamed", so if you move out of the sweet spot, the response becomes very audibly unbalanced. The rear wave can add depth, but only if you place the speakers far from the front wall - a good 5-6 feet for best detail extraction. Others have noted that some of the hybrid ones like the martin logans don't blend seamlessly to their built in subs (this may be a crossover issue more than an inherent design issue, but the fact is that there is a sharp shift from a dipole response to an omni response, which load the room very differently). They also tend to not be very sensitive and operate in very low impedances - a problem for weak little tube amps as dynamics are compromised. I like them, but I don't think they're right for a person with tubes.
Personally, I think dynamic dipoles are the way to go... they reproduce the depth of an electrostat, but with wider dispersion. Most of them, though are active speakers. This does remind me of another excellent speaker which fits well into your price range and is also tube friendly... the Salk Archos:
http://www.salksound.com/archos open baffle - pricing.htm
It still uses an omnipole woofer section mated to the dipole mid so it won't likely sound as seamless as something like a Linkwitz Orion or Nao Note, but I think it's a better option than traditional electrostat/planars, for you at least.
Honestly, I don't think most speakers are right for people with tubes, if they want the speaker to sound as designed, rather than a random sound decided by load reactions. It's not that tubes can't be transparent. But most aren't, and the few that are transparent and not lacking dynamics, cost a good mortgage. In my goal up the "Ladders" for high fidelity, I kind of treat tubes as a "Snake"