There are no hard and fast simple answers to questions like this because the best answer is dependant on each person and their hearing.

Given how little you know about the different codecs and stuff (hydrogenaudio.org is a great forum to get started with the technical details, for example they have extensive threads about reccomended lame versions and settings, as well as encoding to audio transparency and ABX testing) you're probably best off just using mp3 and going back to 2.00 final.

Using Ogg Vorbis or FLAC isn't unreasonable, but will require a lot more of your time and effort to understand and keep up with. Just like ripping to FLAC and then transcoding according to what codec you prefer at any given time.

I would try out --alt-preset standard and if it doesn't sound good enough to you, step up to extreme, and if that doesn't sound good enough try insane. And if that doesn't sound good enough you either have incredible hearing perception (and no compressed audio format is going to be good enough) or you're victim to a placebo effect.

--Nathan