Here's a poll that goes to show that the most powerful tool in recording is your ears.
First, which of the following do you prefer?
One guitar, the same microphone and the same room - the only difference between them all is the position of the microphone in relation to the guitar - microphone placement makes a difference.
Next time you have to record something with a microphone and you don't have the luxury of anything other than you in your own room then put on a pair of headphones and listen to the sound as you move the instrument or voice around the microphone. Before you make a decision then move the microphone to different parts of the room. You may think you are limited by having just one microphone, try this exercise and you'll soon hear just how versatile one mic can be.