I think the biggest variable would lie with the analog sources. If my whole system consists of digital sources and solid state amplification, then I would devote about half of the system budget to the speakers, and probably closer to 75% of the budget if we're talking about multichannel.

My current system pretty much reflects these priorities. I spent $600 on a HT receiver, $350 on the DVD player, and $900 for the main speakers. The 5.1 configuration brings the total investment on the speakers and subwoofer to $2,300.

If I choose to include analog sources, then a much bigger chunk of the budget would go towards those components, because unlike with digital sources, there are very clearcut improvements in audio quality as you move up in price class with turntables, cartridges, tape decks, equalizers, etc. I would probably budget out at least $700 for a turntable, at least $300 for a cartridge, and depending on the quality of the phono stage, at least $200 for a phono preamp. A decent three-head tape deck would run at least $300.

It's the same deal as with speakers. It's not just differences in sound quality when you switch to different speakers. If the difference is not an improvement, then a speaker upgrade is not needed. However, in most cases moving up to a different price class with speakers, you are getting bona fide improvements in sound quality -- audible and measurable improvements that far exceed what you would get with a comparable investment in amplification or digital front end components.