flubadub

Dear All, I am hoping to apply to grad school for fall admission in 2012 (I am from Scotland). I was just wondering how specific I should be in terms of what field of mathematics I want to study? Should I state in my application exactly what I want to do, or be a bit more vague say that I am hoping to let my interests flourish in the first two years of the course? The reason I ask is because I am quite unsure of what specific area my thesis would be in. Thank you very much