For mathematics students, I really like Treil's Linear Algebra done wrong (LADW). It covers more than your usual introduction to linear algebra (and it's free!). A somewhat easier introduction that is still very good is Lang's Introduction to Linear Algebra. His explanations are very lucid and the transition from analytical geometry to linear algebra is very natural in my opinion. If you're more into applications or engineering, Lay's Linear Algebra and Its Applications is my favourite. Note that this is only my preference, you should always take a look at the books yourself before buying them.