Of course keep the RAW files. This is the digital negative (original). Just like the film negatives you take to the lab for printing. You don't bring the photos to the lab for printing do you?
I don't save it in PSD. Only JPG. But I *always* keep the RAW. You'll find that over time your post processing skills improve (gotta persevere, exert some serious effort and all that) and that's when the RAW files come in handy.
been saving in .raw and .psd
but for "multiple exposure" shots, i prefer to save in .psd with all the photos inside the .psd, rather than individual raw