This year we have been using Walter Rudin's treatise as the main text for a standard first-year graduate sequence on real analysis, backed up by Wheeden/Zygmund's book on Measure and Integral, and the two seem to complement each other quite nicely. Rudin writes in a very user-friendly yet concise manner, and at the same time he masterfully manages to maintain the high level of formality required from a graduate mathematics text. To be totally honest, a few years ago my very first attempt at learning graduate-level real analysis in a classroom setting (via Folland's book) was unsuccessful, as I found the exposition in Folland very dense and rigid, and the homework problems too difficult to do. Rudin's book however, is a lot more accessible for the beginning graduate students who may not have had any more than some basic exposure to measure theory in their upper division analysis classes. One point to keep in mind is that, Rudin developes the measure in the more formal axiomatic way, instead of the more concrete (constructive) approach. In the constructive approach, one first introduces the "subadditive" outer measure as a set function which is defined on the power set P(X) of a nonempty set X. One then proceeds by showing that the restriction of the domain of the outer measure to a smaller class of subsets of X (a sigma algebra M), obtained via applying the Caratheodory's criterion, results in a "countably additive" set function that is called a measure on (X,M). (The latter is the approach taken in both H.L. Royden and Wheeden/Zygmund). The formal axiomatic approach is not very intuitive and is less natural for the readers who have not yet developed a certain level of mathematical maturity. Also, Rudin does not discuss some of the more advanced or interdisciplinary topics such as distribution theory (Sobolev spaces, weak derivatives, etc.), or applications of measure theory to the probability theory, both explored in the book by Folland. (Please also note that contrary to the common practice, Folland gives many end-of-chapter notes outlining the historical development of the topics, as well as a good few references and suggestions for further study). All said, I can recommend taking up Royden as your very first approach to measure theory, then based on how well you think you have learned the first course, move on to either Rudin or Folland for a more advanced treatment. Rudin also does a great job on the complex analysis part, a subject not discussed in the other books mentioned above. There are however a few other equally well-written complex analysis books to pick from, for example try John B. Conway's and L.V. Ahlfors's classics, to name just a couple.