How do you determine how much to spend on speakers

I actually think that it is a non-linear function where more you spend on the system on aggregate, less critical it becomes as to what percent of your total budget should be spent on the speakers. Put another way, if someone's budget is $3000 for the whole system, I would say, spend at least 2/3rds on the speakers. If your budget is $8000, then it is a totally different relationship and it will depend more on your priorities (efficiency, brightness, dynamic drive, low-end, mid-range, resolution, even details like off-axis response).
My two cents.

Are you interested in good musical qualities or good sound qualities??
I've had expensive speakers ($8800 Cremona's) and now have $1200 speakers (Magnepan MG12's).
If you are going to spend a lot (like more than $2500) you'd better have the really solid (and dead sounding) walls of a great listening room to go with them or you will still have crappy midrange and treble. I've had a pair of Proac D15's that were beautiful sounding in a high-end apartment but sounded awful in a house I later bought (until I covered all the walls with persian rugs to shut them the heck up).
You can get by just fine with el cheapo MG12's or mini monitors if you have real high end source and amplification components though. It's all about the music, not the sound. Speakers (IMO) don't seem to be as much about the music than they are about the sound. One of the best systems I've ever had was a pair of $875 minimonitors (linn tukans) but they had a $2500 source (LP12) and $7000 preamp and power amp (Kairn/Klout) in front of them.

I have now had the Daber Monitor 3's for two weeks and have had a chance to do some critical listening. I have the rounded cabinets in maple that Steve provides for a small extra fee. They are gorgeous with very high end carpentry work! The first thing that will strike you is the deep, tight bass for such a relatively small speaker. I doubt anyone but the most avid bass fan will see the need for a subwoofer in a two-channel setup. The mids are very satisfying and the highs are clear and precise. Vocals are rendered in a very natural fashion. The soundstage competes with the best. My wife, who is very musically inclined, even prefers them over my Acoustic Zen Adagios. A very different speaker and a matter of taste, but still high praise from a very musical person. I love them both for different reasons. To say that I am pleased with the results would be an understatement. In summary I think this must be one of the best values in speakers out there and they are made in the USA by a small entrepreneurial company. Give them a try - you will not be disappointed!

As a side note the speaker stands for the Volla speakers fit as if made for these speakers (rounded) - got them from MSS HIFI at a decent preice. Steve is planning on making stands for them as well in the near future.

Hello!

This post is nearly 10 years old but the topic continues.

I strongly recommend the source components be where the most emphasis should be put.

Try to make purchases which have lasting, classic value.

In a digital world the music starts with the d/A converters and their power supplies. Today very compelling and beautiful music can come from a universal disc player.

For example, oppo 95, plus a pre-amp e.g. Proceed avp2(used but classic) could be had for $2500.

A citation 7.1 power amp (used) sells for about $800. Also musical fidelity has a good one which sells for about the same price. 3.2CR.

Spend $500 on competent used interconnects e.g. Card as neutral reference or similar. Supra speaker cable buy in bulk with good terminations.

For speakers buy NHT super zero XU for under $200 new.

You will have spent $4000.

Put the remaining $1000 in your mouth and pray for lock-jaw and continue your search for speakers. In two decades the change will be new speakers.

For speakers buy NHT super zero XU for under $200.

I just happened by here and wanted to reply to Appasionata. You seem to really like NHT. I had several of their models from 1998-2008, including the pair of super zeros from the late 1990s. If you like those, try the NHT classic 2s, which can be picked up used. I even have a pair I don't use. They aren't expensive by any means. And I guarantee you the Classic 2s are much, much better than the late 1990s Super Zeros.