What moleskine should I buy?

Yes the pretentious hipster in me has come out. I've been writing for 8 years and I've decided to buy a moleskine because I'm tired of buying loads of crap notebooks that fall apart, but I don't know what one. I do a little bit of drawing, but mostly writing. Is it better to get the medium or pocket sized one? I want to be able to carry it around. Do you get more use (fit more stuff) in the plain one or the ruled one? I can't decide, and its a fair bit of money to spend on a notebook