If you use Maven at all, you should really check out the list of books surrounding Maven and developing with Maven that Sontaype now offers. Judging by the quality of Maven: The Definitive Guide and the quality of Sonatype software, the books on Nexus and Eclipse look equally good.
I use m2e and Nexus in my daily development and can't live without either of them. m2e makes working with Maven from within Eclipse extremely easy and I use it every day. There are just too many great features in m2e to name them and I can't recommend it enough. I also use and am very happy with Nexus. In fact, I run a local copy of Nexus because it speeds up my Maven builds tremendously. If you don't believe me, try it out yourself.