The only time I might do that is if both the game and console were on some sort of sale. I remember I bought Modern Warfare 2 first, because it was on a 30% off, and I bought the PS3 few weeks later on Black Friday. It all depends on if you are saving money, in my case I did.
I dont think its a good idea to buy a game until you have actually for sure decided what game console you are gonna buy. If i were you, i stat thinking what console I should get then think of buying a game for that platform. Right now think about it and save your money in the meanwhile