Go for lossless always I'd say. Your music files are at the very beginning of the sound-chain and you want them to be the highest quality possible.
The better your system gets the more you'll hear the difference in SQ. You might not need it now but later on you could be sorry.
That way you're future proof and won't find the need to re-rip everything later on and believe me, re-ripping a large collection gathered over the years is not something you wanna do!
So if you're on a Windows system go for Flac, on a Mac go for Alac.