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.