Got a couple on the go.
1) The Etymologicon by Mark Forsyth; a thoroughly hilarious and interesting read, I would recommend this to EVERYONE.
2) Imperialism is the highest stage of Capitalism by Lenin; one of his texts while he was in exile in Switzerland, i'm not a communist, but was recommended this as a good and informative description of the development of early 20th century monopoly in Banking and Commodities. Probably not one for the strong willed (ie. those who will immediately discount it for its author) however very interesting and quite short.
3) A Country is Not A Company by Paul Krugman; picked this up for £1 and read a few pages on the bus home from school yesterday, very interesting and perceptive like all of Krugman's writing, however is incredibly short and has large text. Useful for those wanting to understand why America has a failing economic policy (and why many people suggest a solution that wont be successful).