Looking for an amp that punches way about its weight and I can grow with

+ 2 Odyssey ... you won't be disappointed!

+1 on the VTA Tubes4HiFi amps from Bob Latino.  Top notch performers at very competitive prices, and excellent service.  

One thing to remember regardless of the amp you buy - it is critically important for you to keep the smoke inside the unit!

Parasound A21+ , punches like Mike Tyson. 

I just purchased a pair of ESLs and an 800X sub but I don't get the push for tubes I frequently see here and elsewhere on the forum. 

A bit of background, I was a Navy tech when tubes were the primary device for amplifiers, oscillators, etc.  I went through the transition to transistors, MOSfets, integrated circuits, large scale integration, etc. to the present as an engineer.  First, tubes are highly unreliable, I replaced hundreds of them in gear built to Mil-Spec which is far higher quality than consumer electronics, second, they all add coloration to the sound so you are not getting true high fidelity because even the best do not have a flat response over the entire audio spectrum, especially when compared to modern day solid state amplifiers.  Generally there is a roll off of the high end that some people like but one shouldn't fool oneself into calling it high fidelity.  Second, the quality of tubes made today are not up to what they were when tubes were it.

As someone famous said the best amplifier is a straight wire with amplification.  Most modern class A/B and D amplifiers have a far flatter response than any tube amplifier and lower distortion.  I was involved with high end audio in Miami back in the 80s when Krell and Mark Levinson solid state amps were the rage.  As good as they were, and they were good, many class D amps built today from companies like Hypex and IcePower in the Netherlands have better performance, are far more environmentally friendly in that they are very efficient and use little wasted power in the form of heat.  Very good class D amps can be had for under $3K.  You can probably find some very good class A/B solid state amps in that price range too.

No chain is stronger than the weakest link.  Usually, that link is the speakers.  People spend in-ordinate amounts on DACs above 48KHz, speaker wires, interconnects, etc. yet the best source material is recorded at 48KHz in the studio.  Think of it like taking a picture with a 12MB camera and then trying to enlarge it to a 24MB image.  No amount of trickery will make it match a true 24MB image.  The same is true for sound.  Can you fool yourself into thinking you have a better image?  Sure, we fool our selves on lots of things all of the time.  Without a comparison the mind will fill in the blanks, but put two images of the same scene side by side, one a 12MB sensor image and the other a 24MB sensor image and the eye quickly sees the difference.  The same is true with sound and to add insult to injury, our memory of sound is simply not very good.  Allow a little time between samples and we just can't recall with sufficient detail to be certain.

Buy what makes you happy, it is your money.  :)