40% savings is a lot. You can hold up to like about 66% more data with the same amount of storage space (I think I did my math right).
I usually see pop and rock music get compressed down to about 70%. Quieter classical music might be compressed down to 30-40%.
I suggest using FLAC if you are planning to use other players in the future. Otherwise, you any lossless codec you are comfortable using.
If you use foobar 2000 and FLAC, you can download an extra tool called flacattack which automates the process of ripping and encoding to FLAC. In addition of FLAC , you can choose one other encoding format too. So in the end, you can automate the process to generate a wav file, a FLAC file, and a mp3 file. The only problem I have with flacattack is its installation process. Installation and configuration requires some tinkering and some extra software utilities, especially if you need to embed cue files into FLAC.