The Taurus MkII is a good head amp, but it has been superseded by the equal sounding Cayin iHA-6 Balanced Headphone Amp, which is half the price ($999).
http://www.innerfidelity.com/content/innerfidelitys-wall-fame-headphone-amplifiers#cI86mmhX31EKWp0L.97
For a transistor based head amp i still prefer my Audio-GD Master9 over any other transistor based head amp. It is also a great pre-amp.
To my ears it is unbeatable for sound quality, power and neutrality, yet only costs $1430.
It sounds as good as, if not better than the $3500 Simaudio MOON Neo 430HA, yet is less than half the price.
The only disadvantages of the M9 are it runs very hot due to pure class A operating mode, and is large and heavy.
The Cayin iHA-6 is lower cost, smaller, lighter, and runs cooler; yet sounds very good.
As for the ultimate head amp, for me it would be the $8400 tube based Lampizator Big 7 Head DAC.
http://lampizator.eu/Fikus/HEAD_DAC.html
http://lampizator.eu/Fikus/PRICE_LIST.html
As for headphones, i now use Focal Utopias, with balanced pure silver cable, to my M9.
I also bought a Stax 007mk2 with KGSSHV Carbon electrostatic amp from
http://www.mjolnir-audio.com/