Are monoblocks better than stereo, with tube amps?

I am only in the research phase of audiophilia. My present system includes a creaky NAD 150w amp and ghastly sounding speakers from a "rack system" circa 1988 Stalingrad. Anyway, I am hoping to eventually save for a tube set-up with a kind turntable and sweet, costly speakers. I am wondering if there is any advantage to using a monoblock system for amplification and why.
I love monoblocks. They typically have double the power supply than a stereo amp which gives them great authority and the feeling of more power even if on paper they are the same.

They also have no crosstalk between channels. I think this advantage is bigger than many give it credit for. Imaging improves greatly with no crosstalk or intermodulation distortion. So does the "space" in a soundstage.

IMO, it is worth the extra money over the stereo version. Good luck and have fun. Arthur
As above I agree, they are not really rated at higher output but cleaner and more balanced due to the increased power supplies, mainly bigger transformers dedicated to each channel and they don't get to close to power saturation sharing everything with two loads on 2 speakers, opposed to a single load, and normally more than likely an increase in capacitance filtering as well... With tubes especially I could see how this would benefit being a lower noise ratio.
Manufacturers of high quality components equip their stereo amplifiers with sufficiently large enough power supplies to make it a non-issue.

I would be far more concerned with design, parts, and build quality.
Me 2 on what Aball says.
Unless you are interested in "no holds barred" products, a stereo amplifier will do everything that a set of monoblocks will do.

There's no doubt that separating the power supplies and using a very short run of speaker cable with a long run of interconnect is a good thing. But there are some REALLY nice two channel amplifiers out there that are amazing.
Modulation of the power supplies is the issue here. Since almost nobody regulates the power supplies for the output section of their amplifiers, monoblocks will sound better for this reason alone. The result is greater authority, improved soundstage and a blacker background. BTW this has nothing to do with whether it is tube or solid state!

Stereo amplifiers can get around this problem by having separate power transformers and supplies for each channel. Then the only concern is proximity, which can be dealt with if wiring and layout concerns are addressed.
All other things equal, yes.
Not necessarily and in the end it is the sound that counts most. I would not let mono-bloc versus stereo make my decision.
True that!!
thanks for the responses, which have led me to more questions.
Czbbcl, atmasphere, unsound; what do you mean by 'modulation of power supplies', 'proximity', most importantly, what factor involving amplification's sound is more important then the monoblock versus stereo argument? Also, I understand a bit about why speaker wire should be shorter than interconnects, but should interconects literally be quite long (forgive the obtuse questions)
In simple terms, modulation of power supplies refers to the effect different channels drawing from a shared power supply has. This may not be as big an issue with stereo amps that are "dual mono", or even to a stereo amp that has a very robust power supply. Proximity usually refers to the potential for channel cross-talk amongst other things, such as power draw, heat dissipation, placement ease, etc.. The ultimate sound is the most important factor involving amplification's sound. Seperating the channels is only one aspect of designing an amplifier, and certainly not the most important one, as Atmasphere and Czbbcl have wisely pointed out. As I said, if all else is equal there can be advantages to mono amps, but, in and of itself there are many other important considerations, especially when there are budget considerations. That is why I use a stereo amp, even though, I appreciate the advantages of mono amps. As to the relative lengths of interconnect vis a vis speaker cables, there are differences of opinoion here as well. Decisions as to relative length may be best determined, specificaly to each system (including the specific cables). Personally, I usually prefer to use shorter interconnects and longer speaker cable. There are some other advantages to mono amps as well,that again, in themselves don't necessarily make them superior. I humbly suggest you review the archives. You will find a quite a bit of discussion on mono vs. stereo amps and short/long interconnects vs. short/long speaker cables.
I prefer to run mono amps which allow me to run very short speaker cables with long interconnects. OTOH, I run everything balanced, so I can get away with that.
The advantage of a rock steady power supply can be exaggerated. Let's say that the music momentarily requires a 40 volt level at the speaker. The amp's power supply is 80 volts nominal. No problem. Now suppose that due to prolonged high rms level signal the power supply "sags" to 70 volts. Can the required 40 volts be delivered? Sure. The transistors just turn on a bit more. In fact, 60 volts, or even 50, might be the nominal power supply voltage for a lower rated version of the amp that is perfectly capable of the 40 volt output.

Some amps are deliberately designed with a high voltage power supply lacking ability to maintain this voltage very long. This enables the amp to follow music signals much better than its continuous rms power rating would suggest.
That "rock steady" power supply is expensive, and so long as your signal is music it may be an unnecessary expense.
Like Unsound I also run longer speaker cables and prefer shorter interconnects. I am also a cj fan and that has also been their recommendation concerning their equipment.
The more practical aspect which has yet to be mentioned is that monoblocks can get you the biggest dual-mono power supply (plus heatsinking capacity in traditional solid-state amps, or output transformers in traditional tube amps) without creating one inconveniently large and heavy chassis. Who really wants to contend with a 200lb. amplifier? Of course, you pay for those two chassis instead of one, and need two power cords. But with the new smaller switching-amp designs these issues can be finessed -- you can have a powerful stereo amp with dual-mono supplies without it getting too large or heavy, or you can have separate monoblocks for cable length flexibility without paying for (and needing to place) two full-size chassis. So I think it tends to break down this way: for high-powered tubes, monoblocks are typically the way to go, while lower-powered tubes can work well either way; for traditional solid-state either configuration can work well, with the ultimate high-powered edge going to monoblocks; for switching-amp solid-state, you pick it.