So I was asked about what my top five recommendations would be for Groovy/Grails resources so I thought I would post them here to get feed back and other ideas from the community. I decided to break it up into five categories.
1) Web sites
Of course the top two would have to be the main Groovy and Grails sites themselves. Not just because they are the home of the respective projects but because both truly are good resources with plenty of examples, documentations and links to mailing lists and other resources. Others not associated with elements already to be placed in following categories might be the Spring and Hibernate sites.
Sven Haige started the Grails podcast and was recently joined by Glen Smith. They do a wonderful job with the podcast and it's a great resource for the community.
The Java Posse is high water mark in technical podcasts and I also enjoy Software Engineering Radio.
3) RSS feeds
There are a lot of blogs, rss feeds, etc. that a person can track down. The following three aggregate such feeds and provide a good starting point for locating feeds you resonate with:
http://groovyblogs.org http://groovy.dzone.com/ http://www.groovyongrails.com/
Focusing on IDE's the first I would have to recommend is IntelliJ IDEA as its Grails/Groovy support is top notch. It's commercial, but well worth the cost and I believe the best of the those out there for Groovy Grails work period.
Following this I would (personally) would go withNetbeans 6.1 as it also now has Grails support. However, you need to use 6.1 development builds. The plugin home page is at: http://plugins.netbeans.org/PluginPortal/faces/PluginDetailPage.jsp?pluginid=6265
Eclipse also has support and in fact was the first to do so if I recall correctly. However, I have not heard much about it and suspect its support has not been a high priority. Many love Textmate (for good reason) and its various bundles and while on the non-IDE side of software one could likely do a lot with Jedit as well (I have).
Both Teamcity and Hudson provide build environments and code coverage (by way of plugins for Hudson) for Grails projects. Hudson requires a little work for setting up Grails builds but there are some nice blog posts on such efforts. Again the IntelliJ produced Teamcity shines in its Grails support right out of the box.
Groovy in Action is a wonderful resource to have as is The Definitive Guide to Grails. There are several new Groovy books coming out and more likely to follow as the Groovy/Grails community continues to grow.
Would love to hear other ideas/comments.