Just so there's no ambiguity, lossless is lossless regardless of the filetype.
So Wav, AIFF, FLAC, Apple Lossless, Ape, WMA lossless, etc. all ripped from the same 16-bit 44k source are going to sound exactly the same, because the
are actually the exact same data (provided there were no ripping errors, which there can be). The only difference is the metadata that the file container carries with them. For instance, the difference between a .wav file and an .aiff file is simple that the AIFF contains much more information embedded into it that makes it useful for manipulating in music programs.
As far as compression schemes tend to go, FLAC is more or less the clear lossless winner, as it's the most widely supported across platforms (you haven't stated whether you have a Mac or not, I think), and can handle multi-channel audio and high resolutions perfectly.
Lossless compression all hangs around 55-60% so you won't get much difference there.
With lossy compressors, it's all up to your ear. AAC, Lame MP3, OGG, everyone claims one of these sounds better than the other at any given bitrate. To me personally, I have to deal with people in the music industry who think they can hear the difference between a 96Khz wave file and a 192Khz wave file (hint: they can't), whereas I'm of the opinion that almost nobody is going to be able to tell the difference between a 320kbps MP3 and a full-quality CD wave file in all but the most critical listening environments.