Normally, I will only buy what I really love. And I never buy "backups" because I know something else will come along that I'll love equally BEFORE I finish the first one.
However a couple of times I was "swayed" by the hype and bought something (ie: metamorph) because everyone raved about it so much and I was afraid of missing out on the color of the century. Well, I ended up not liking it, as I had first assumed.