despite the numerous replies here is masterpiece yet to be mentioned :

Alain Connes' Noncommutative Geometry

This is a most brilliant introduction and overview of many modern aspects in all of the areas

• Analysis (in particular algebraic)
• Geometry (in particular algebraic, non commutative and infinite dimensional)
• Topology (in particular algebraic and analytic)
• Statistical Physics and Quantum Theory

It is simply just perfect in every aspect - the pedagogical style, graphical design and illustrations, historical side notes .... but most of all ... the originality of the mathematical thought!