Currently I'm using Eclipse Indigo (v3.7) for Selenium WebDriver automation tests with Java. There is also Eclipse Juno (v3.8 - 4.2) available that I have never used.
What's the difference between Eclipse Indigo and Eclipse Juno?
Since 2006, the Eclipse Foundation has coordinated an annual Simultaneous Release. Each release includes the Eclipse Platform as well as a number of other Eclipse projects. So far, each Simultaneous Release has occurred on the fourth Wednesday of June.
Eclipse Indigo corresponds to platform version 3.7, while Eclipse Juno - to platform version 4.2. Juno has a lot of improvements on the UI, but this results in a bit slower performance that the previous versions. Personally, I would prefer using Indigo rather than using Juno.