Tell me about your digital music collection

If you have a lot of CDs and have set up a good home system to listen to them online (i.e., on a hard drive rather than having to pop each physical CD into the player to listen to it), I'd appreciate some advice. If your goal were to put the physical CDs in the attic forever, no matter what fancy encoding technology appeared in the future, which format would you choose? Would single-file-per-album FLAC plus embedded cuesheets be sufficient? Or is there reason to drop to an even lower level, such as ISO or BIN?

I don't care about file size; if it takes 747MB per CD, so be it. I do care about the archive format being usable; hence the attraction of FLAC, which my Squeezebox can play, versus ISO/BIN, which are cumbersome as an audio source. I don't care about hybrid data/audio CDs. I definitely do care about gapless playback.

I made a mistake back in 2005 and ripped my collection to a lossy format. My penance is re-ripping the whole batch. Please help me do it right this time.