Value of a preamp?

I have also experienced the beauty of synergy between a preamp and amp. More often than not, the same brand of preamp and amp gives the best performance. But there can be exceptions.

My favorite preamps as of late are as follows:

Mola Mola Makua - $12,200 as a line stage. Phono card adds $3,000 and DAC card adds $8,500. Transparent, neutral, and dynamic!

Audionet Pre G2 - $23,350. Great body, transparency, dynamics, and 3-D.

Audionet Stern - $48,950.  The most transparent preamp I've ever heard. But it also has the most accurate tonality, best bass and bring things to life dynamically in stunning fashion. 

@ddgtt 

Would that mere mortals could afford them...

@ddgtt 

I agree.  A good preamp is the conductor of the symphony.

Depends on your DAC! If you get the new Lampizator Poseidon, it does not need a preamp, because the impedance level matches any amp. 
same with playback designs.

fwiw, i just did a listening session with a naim power amp and a ps audio 5.0 preamp, which has both an active and passive (straightwire) mode. at the same volume, the active mode had significantly deeper (but less sculpted) bass and more dynamic slam, while the passive had less overall oomph but a lot more high-end detail and, predictably, a lot less coloration. we all preferred the passive, except for vinyl, which sounded a little flat. of course, i'd expect impressions with different gear.