There is two available Eclipse plugins for Maven :
m2eclipse seems to be the oldest but the more robust. Is there any key differences between the two ?
Which one should be chosen for a project starting today and why ?
UPDATE: m2eclipse is moving to eclipse.org and will be included in the Indigo release train (Eclipse 3.7). See m2e at Eclipse: What will this mean for you? and m2eclipse is moving to eclipse.org!. The accepted answer is thus even more correct.
I choose m2eclipse since it is stable and have all that I need. Especially ability to resolve dependencies inside workspace.
I tried the other one some time ago and didn't like it. It was to buggy so I gave up quickly.