I've been mostly using MPC at --q6 with the newest version of the encoder (which is eqivalent to --extreme in the older versions). Most people recommend --q5 (--standard) as being pretty much transparent, but I use --q6 just because.... I'm not really worried about hardware compatibility or portability (I used to love taking my portable cd player everywhere, but now I just find listening to music on headphones annoying). Also, MPC encodes at about 5x on my machine while MP3 and OGG only encode at about 3-3.5x, so that's cool.
I have been playing around with the new OGG at -q7 a lot the last few weeks. I'm not really sure that I can hear any differences between OGG and MPC, though.
My real desire is to go completely lossless with APE or FLAC, but the size of my cd collection just doesn't make that feasible right now. Although, I have been using APE for copies of my vinyl, since it's so much work to rip and I may want to burn them to cd at some point. I've also been using APE for copying the good tracks off cds that I've decided to get rid of.