Just because it's pertinent and works, I'll interject this once again... and from time to time for the newbies and other's.
A great front end makes even decent speakers better.
Determining your goals in advance will make your speaker choices fewer and to some degree easier.
Easy impedance loads and good to very good efficiency ratings will also afford one far greater flexibility as one tries this and that with regard to system components (amps) along the way.
Middle of the pack $4K to $6K speakers can sound like greatest speakers on earth when the front end attached to them is up to snuff.
Great speakers do not make great front ends... but fine electronics do make very good speakers great. true too there are some very good quite forgiving loudspeakers on the market and even so so gear will make them sing pretty well. Apart from those units however, refined well heeld and resolute speakers require the same in the signal being fed to them.
The keys will always be the same... room size... room acoustics... and the amp feeding the transducers being mated properly to their particular needs.
Systems that are balanced will yeild results beyond the sum of their parts.
So spend what you wish on squeakers but do remember, it's a symbiotic relationship and not a parasitic relationship. Speakers which remain at one third to one half of the total enterprise should be sane enough choices.
The short answer IMO seems to be to spend what you can when you can with the notion in mind that speakers do play a significant role, but not THE role in an excellent sounding system... as everything matters... and I do mean everything.