I'll be using FLAC - I've been very impressed with the B&W downloads.
I also recently got The Beatles' remastered White album in stereo from my wife when she was in the States and then downloaded the Mono version in FLAC. (I think I've spent enough money on ass-sounding Beatles discs over the years to warrant a freebie

)
No discernible difference between the two as far as SQ goes.
The music, however, is a different story altogether

I plan on getting all the remastered albums in mono - they're that awesome!
My system is a real pick-'n-mix:

Digital: EAD Transport and DAC
Phono: NAD 533 with Goldring 1012
Pre: Electrocompaniet Preampliwire (that was recently given an awesome-sounding overhaul by Rudi)
Power: Daan Jacobs Monos (also modded by Rudi)
Power: Steinhart 100W Monos
Speakers: Quad 22L2
Cables: Dirt cheap stuff from my local mom & pop electronics shop