At which bitrate in Ogg would be the same quality as MPC standard?? 64/96 or 128??

None of them.

Speculation:
I suspect it to be somewhere in the -q 5.0 to -q 5.5 region

Heh yeah, sure Vorbis is better at 64 or 128kbps than MPC standard?? Hello!?!

MPC standard is clearly better than equivalent Vorbis average bitrate. It can't be said so simply which -q has the same quality as MPC standard, but I wouldn't start below -q7...

It just can't.

MPC very effectively stores the valuable information that it needs to sound transparent already in "--standard".
Ogg, seems to work well at q6, but still it is not an "--alt-preset standard", neither a MPC --standard. Higher q will have more space to get a good result, but to resume, ogg is still not as well tuned as MPC. (Also, It's more difficult to tune OGG than MPC, due to the nature of both)

I hope that OGG will get tuned better by people, like LAME had, from now on.

Where on earth did you get this idea?
and WHERE did you get those numberS?? 64/96 & 128!!
omg no... no!

I have my doubts about this claim - I think it warrants testing rather than speculation.

--
GCP

Is it enough having a sample (that awe32) that with q6 is not transparent (when listening carefully!) using.. mm.. can't remember which bitrate, whereas MPC --standard was transparent and averaged 245kbps?

Ok,one sample is not much. More even when it seemed to cause quite much problems to MP3 but I still hold that point.


BTW: if you meant the "q6 works well" part, I said that one because it is where the lossless stereo is said to start, and with not difficult samples, (I tried just few), seems to cope with them.

BTW2: Mmm... now I realize you mean the "--alt preset standard" so... LAME, so MP3, and yep... it performed worse in that sample... Mmm... as you said... I should test more.