i think that the very best one that is going to be the most help for you, as a student, in developing nursing diagnoses and nursing interventions to go with them is nursing diagnosis handbook: a guide to planning care
currently in it's seventh edition and published in july of 2005, so is very current, by betty j. ackley and gail b. ladwig. it runs about $39. the author, doenges, has one that is similar as well. if you chose doenges, check very carefully because she has a number of careplan books in publication and they are all structured differently. some are by medical
diagnosis and others by nursing
diagnosis--there is a difference!
here are some recent threads on advice for nursing care plan books that you might also want to read through: