Some of the new features include Maven Integration (via M2E, a new project with this release), support for Hudson (via Mylyn), as well as the integration of EclipseLink 2.3 (which does multitenancy and more, see release page, blog). Support for Java 7 is expected for the September update release. The "Eclipse IDE for Java EE Developers" bundle is 210 MB.
Support for GlassFish is available today as well! The GlassFish plugin now offers the ability to deploy to remote running GlassFish instances and supports version 3.0.x and 3.1.x (including recent promoted builds). That GlassFish plugin for Indigo also works for the earlier Helios release. The update to Oracle Enterprise Pack for Eclipse (OEPE) will come with the Indigo September (3.7.1) update.