I could be completely mistaken, but I think the OP is in South America, probably Argentina. I don't think pricing is the same there as it is in the US.
Those are all good games, and you really can't go wrong.
If I could add one of those games to my collection and they were all the same price, I'd take Creature just because they seem to always be too expensive otherwise. Around here, it would be easy to trade Creature for either of the other two, in the future.
I do think Creature and Shadow are both fun games. I enjoy Creature a little more at this point, but it's shallow. Shadow has grown on my quickly. I think Shadow would be the most fun to own long-term. Road Show has cool toys and the widebody is nice, but I've never really felt like I was accomplishing anything while playing it. I would gladly own that one so I could put serious time in on it, though.
I've never played Indy 500, but that's probably about as good a deal as Creature, and I usually hear good things about that one.