I'm a Spanish Professor and these are by fat the best dictionaries for college students.

BRAND NEW Diccionario Practico del Estudiante / Student Dictionary (Spanish Edition) [Hardcover] Sells for $20 on Amazon (Spanish to Spanish)

And Larousse Diccionario de la lengua Espanola Esencial (Spanish to Spanish)

I'm also adding two textbooks on Latin American Icons and the Classic Lazarillo de Tormes (Free of Charge and in English)