I like uncompressed .jpg the best myself. .Uncompressed TIFF is my second choice. I loathe all forms of compression and don't use any of them, LZW and jpeg compression will both ruin your image but if you set the jpg compression to the lowest setting the image retains it's quality through many resavings. Zipping won't effect image quality at all. Gif may be 'lossless' in some technical way but it reduces the number of colors in the image and generally screws it up pretty badly, if you care about how it looks. PSD and PSP formats are fine until you go to put them out, then you should change to a more universal format. About the only time I save in those formats is when I want to save an image with layers still separated, I think you need TIFF or PSD to keep alpha channel information if you use that.

"Your work is to keep cranking the flywheel that turns the gears that spin the belt in the engine of belief that keeps you and your desk in midair."

Annie Dillard