Wow Jerry there's such a thing as over simplification.
SU-4 is a wireless flash mode that triggers the flash when it sees an incoming flash signal. This works with every camera regardless if it's a point and shoot or a Canon 1Ds. Everything is controlled by the flash, the flash uses A mode (it checks it's own light reading depending on what it's pointing at) or it can be set to Manual mode.
Remote is Nikon's propriety Creative Lighting System mode. The flash is given a Group number and all you can control is the zoom head on it. Everything else is controlled from a Nikon CLS Commander flash like the SB-800, or the popup flash on the D80,D200,D300,D3 and other recent Nikons. This has the advantage that because there's actual data communication happening the camera can ask the flash to fire a TTL metering burst, measure the light, and then tell the flash how it should fire and when. Full iTTL flash metering is maintained using remote mode.