Question: I am really tired of struggling with Maven 2 all the time. Build tools should not be in the way. Recently I have been looking at Buildr and Gradle. Maven 3 seems to fix some of the struggles. So, what should I go for now? Buildr? Gradle? Or wait a year for Maven 3?

Answer: 
I wouldn't expect too much from Maven 3. The people behind the Maven pedigree of build tools have always held the assumption that project builds are homogeneous, that is: all build problems fundamentally boil down to the same problem. This view of the world can be held fairly consistently in the face of opposing views but comes at a cost. The absence of scripting logic in Maven ("when you want to script you know you're doing something wrong"), the cumbersome plugin API ("no ordinary Maven user should want to write a plugin") and the central repository ("we all have the same dependencies") are all testaments of this overarching assumption.

In the real world build problems are heterogeneous because people build software for a wide variety of reasons. They all 'develop' like we all 'drill holes' once in a while for solving unique problems. Regardless of your level of abstraction you'll always find similarities when comparing arbitrary build problems. It is the reveration of these similarities and the condemnation of differences that is the downfall for Maven's design and the reason why it draws so much flak. Basically, Maven is authoritarian and utopian in its outlook.

PS: Maven has good features, like convention-over-configuration and the idea of using repositories (the Maven implementation of this idea is troublesome).
Maven 2 and 3 have both been working perfectly for me on a variety of projects. I am currently using Maven 3 alpha 7 which works very well, especially in conjunction with the Eclipse Maven plugin.

Maven integrates seamlessly with Ant - in both directions. In my current project, we invoke Maven from Ant multiple times in order to perform complex integration test. Likewise, we use Ant via Maven's AntRun plugin, and we also wrote our own Maven plugins. This, by the way, is a matter of minutes and boils down to writing an annotated Pojo.

Maven gets a lot of flak because many developers don't like rules or conventions. Quite simply, nobody forces you to use Maven. If you want ultimate freedom - by any means - re-write your own build process for every project you join. However, if you like to create software rather than re-inventing the wheel with a custom-made build process on every project, go for Maven.