Burned CD to OGG, bitrate? Options

[humulos]

So I have this past year discovered the wonder that is FLAC, and I absolutely adore it. Then I discovered OGG (well, looked into it, I've known its' existence for a few years) and was overjoyed by a great solution for keeping majority of quality on my portable audio player.

Sadly, before I discovered these things, I have been using Mp3. Not only that, but I started off using LOW bitrate Mp3's because I didn't realize that there was a difference! (never tested) I eventually burned something at higher quality and then realized my mistakes, which sent me on my journey to discover OGG. But now I have a problem.

I have several burned CDs that are my only source for some music. Whether I burned them or a friend burned them for me (none of my friends have ever understood quality either it seems) I have them, and I know they weren't burned from lossless. So this creates a problem for me. At wot bitrate to I need to rip these files? A tough question to answer, for sure. I have no idea the original bitrate of the files put on any of these CDs (they were all either Mp3 or WMA though, some AAC maybe) and am not sure how to determine this. In fact, I am beginning to think there isn't a way. If there is, please let me know! My primary goal is sound quality, but my secondary goal if possible is low file size. I figure I might as well not waste space on quality that doesn't exist.

So if there is no way, I guess this should be my question: assuming that each CD was burned from 320kbps Mp3 (which I doubt any of them were, I just want to be safe!) what would be a proper OGG bitrate to rip them to? I know I will lose quality, that's a given, but I want to lose as little as possible while minimizing my output size.

Thank you for your assistance And as a side note, I do plan on obtaining as many of the original CDs for these albums as possible. This is just a temporary solution until that becomes possible (CD's may be cheap nowadays, but I still can't be constantly spending money on them!)