getting a new home cinema system next week and ive noticed i can connect the dvd player by normal scart or by rgb scart so is there much of a difference in both ?

Depends, there is a difference but most people won't see the it.

RGB is better and most reasonable home cinema equipment will have RGB enabled SCART inputs and outputs on. Usually it's something like AV1 is composite and RGB, AV2 is composite and S-VHS and AV3 is just composite, or something along those lines.

RGB is by far the best.
Just make sure that the scart lead you use is 'fully wired' (all 21 pins are connected)

The jump in quality between S-Video and RGB is huge!! - You'd DEFINITELY notice the difference.