If I had a case with a glass side and a desk it would fit on, maybe I'd bother with any fancy visuals inside the case at all, and perhaps put an appropriately themed figure somewhere. As it is, my current case is a coffin with parts concerned with price/performance in it, sitting to my lower left. My next one will be the same.
Even if I did have the above, I'd probably still prioritize airflow and not bother with lighting and whatnot, to be honest.
Of the figures/cases in the OP, I prefer:
Portal. Robotic figures inherently work better in this environment, I think. And it does the portal colors. The fans are perfect for that.
And..are those Gundams, I don't even know, but that case is nuts. Looks like a 16-bit game level diorama or something and is pretty cool.
The lighting in the Darth Vader one is on point. And Funko Vader is probably one of the better Funkos. Doesn't have the usual generic zombie-eyed deformed square head. Has some personality, and the reflections work well on it and that Spaceballs helmet.