Eclipse 3.1 should be out in a few weeks and looks like its a going to be a winner according to What’s New in Eclipse 3.1 @ JDJ.One of the associated Eclipse Projects, the WTP looks interesting:

The Web Tools Platform currently has two subprojects: Web Standard Tools (WST) and J2EE Standard Tools (JST). WST provides a common infrastructure for Web applications development and provides editors, validators, and document generators for a wide range of Web languages (HTML/XHMTL, CSS, JavaScript, Web services, SQL, XML, XSD, WSDL, etc.). You can also publish and deploy, run and debug, start and stop Web applications on target servers (see Figure 6). WST also includes a TCP/IP Monitor server for debugging HTTP traffic (including SOAP Web services), and a Web services explorer that is very handy for testing. Currently it also has support for relational databases management and queries, though that may be moving to the new Data Tools project soon.