I like the MGM edgespot design once you remove those inverted images, and while you could probably get away with leaving out the casino name on the edge, I think you have to have some kind of text in the inlay. I like the idea of some sort of Tournament classification, but that is because the home games I play in are all tournament style.
With the edgespot design I would be tempted to vary it for each denom.
For example, assuming you did not want the MGM Grand on the edge you could use just two of the 5 edgespot waves shown on the chip, using the same placement. This could be your 100 denom and your 25 could have no edgespot waves. Then for your 500 denom, maybe go with three edgespot waves but now they are placed 3 times around the edge, and your 1000 chip could have 4 of these waves placed at 4 spots around the edge.
For colours, I would go non-traditional since you are looking at a 4 chip set but like you said, it is all preference. I think I would include a white/grey, purple/pink, orange/yellow, and a black/blue but that is just me.
