To be a good Starcraft II player you need to have solid mechanics, being able to keep up your macro in the long run in the game. While using cheese strats will get you promoted in the short run, you will eventually start facing opponents that will be able to hold them off, and you'll find yourself back in the lower leagues in no time.
When I first started playing, I used cheeses much like you say you do.I was placed in gold league, and won a couple of games the same way.But in a few days I got demoted all the way into bronze.
If you start practicing solid mechanics and macro you'll have a good steady increase in skill level, and promotions to upper leagus will follow shortly.Sure, you're gonna loose a few games if your opponent uses a cheese, but don't worry, in the long run you are way better off.
Regarding what Day9 said about using a single strategy if you find that works for you, I don't think he was reffering to cheeses.Just find a solid, general build that you like(like a 3 gate robo if your protoss, or spanishiwa's build for zergs), and stick with.These are pretty good macro oriented build that can hold off early pressure and allow you to win in the later stages at the game and at the same time you will find that your apm, macro, resource and unit management will improve drastically.