As they say: a mastering engineer's most important tools are his ears and experience, but for those who are interested these are the tools I use:

STUDIO:
Custom studio acoustic design by Jim Keller @ Sondhus.

ANALOG/DIGITAL CONVERSION:
Cranesong HEDD 192
Universal Audio Apollo 16 Mk.2

MONITORING + ROUTING:
Geithain RL901K monitors
Dangerous Liaison
API The Box console

ANALOG COMPRESSION:
API 527
Manley Vari-Mu
Shadow Hills Dual Vandergraph
Vertigo Sound VSC-2

ANALOG EQ:
Heritage Audio 1073 500 (pair)
Manley Massive Passive
Millennia NSEQ-2 FF
Kush Clariphonic
Pultec EQ-500A (pair)
Siemens W295b

ANALOG MISC:
Black Box Audio HG-2 Tube Saturator
Dangerous S&M
Otari MX5050 1/4" reel-to-reel
Rupert Neve Designs Portico 5014
Rupert Neve Designs 511 pre amps
Siemens IA line amps

DIGITAL PROCESSING:
Bricasti M7
Eventide H8000FW
Lexicon PCM90
Lexicon PCM81
Symbolic Sound Kyma
TC Electronic M3000

PLUG INS BY:
Audioease
Fab Filter
Izotope
Sonnox
Stillwell Audio
Universal Audio