I love slides! I own a 35mm projector and a 6x6 projector. Very spectacular projected. But I also love diving into the slides with a good loupe (I actually use a 50mm lens wide open as a loupe) in front of a white page (try blank.org) on my computer screen. The polarized light from the screen works very well to eliminate the Callier effect of regular light (which tends to make all the tiny imperfections of the film base too visible). I need to hold the slide about one inch from the surface of the screen in order to avoid seeing my screen's pixels through the slide). It is a mind-blowing experience where you feel as if you could touch the subjects.
I shoot 4x5 slides too and always get a kick out of gazing into them with the loupe but I also got amazed how good they can look projected in my 4x5 enlarger. The light is dim but wow it feels like you could touch the virtual print.