My current list would contain the following systems, with no order:
Omicron Delta: The green-yello star and the ring around it gives this system the right feeling of being an unexplored region. Burgundy: The amount of detail regarding the sun, the planets and other objects in there make you feel small. Omicron Major: Creepy nebula which hides some secrets below. What else need to say? Sigma-17: The background of '17, the nebula, and only one jumpgate make it a perfect example of being the frontier to wild space. Frankfurt: Only a drive-through, Frankfurt can show us that house space is not as safe as many think, at least that's what I feel
There are many other really beautiful systems like the new Omicrons, but I wanted to keep the list short.