I used Spring STS for a few months before starting at Lab49, and found it to be a good distribution over the standard Eclipse build. It has lots of extra productivity features for Spring based development some of which are not available by downloading Spring plugins and adding them to a normal distribution.
The things I like best are:

• The edit, navigation and search systems now support the spring annotations. So now you can navigate and search for beans declared via annotations.
• Ability to include new XML domains in the spring configuration from a popup list.
• The enhanced XML editing support now has inline error checking.
• This XML editor also supports completion and checking of class and bean names.
• Roo shell looks interesting too.

Roo and Roo Shell
The Roo system looks great. Its a system to generate and support a JEE system. The roo shell can be used to configure JEE components. You can have a basic website up in seconds. Like Groovy and Grails you get spring standards built in, and your not dependent on the Roo system once your finished.

I am going to take a proper look at it at some point.

                          

The spring integration project embodies principles found in the Spring Framework and Enterprise Integration Patterns (Hohpe and Woolf, 2003). The book and project are worth a look for anyone working in that space.

• Spring Integration Project
• Spring Integration in Action, Manning Early Access Program