EMF has changed the packaging in 2.4. You need to download an additional jar for docs and source for EMF and XSD. While this might be a good news for those who are bundling EMF in RCP apps, not for the early adopters of WTP. If you are an early adopter, then probably you may want to do vote for the all-in-one package for the milestone builds.
Related:
How does EMF finds the right parser?
Converting EMF Resource to Platform Resource (IFile)
EMF Packing changes in 2.4
Using EMF with XML Catalog
Explaining an action or describing an object with fewer words is tough. Showing them as 16x16 icons is even more tougher. Eclipse has a wonderful collection of icons. The best part of it - the whole set is consistent in sizing, coloring and styling. (I personally feel that icons like the filter 
, jar library 
, plugins 
are brilliantly done). You can reuse them in many places in your own plugins/RCP Application as well. AFAIK, these icons are under Eclipse Public License and so you should not be falling into any legal trap for using these (don't take my word, I'm not a lawyer :-).
Many common images (undo, redo, file, folder, cut, copy) are available thru the org.eclipse.ui.ISharedImages interface. You can get them with IWorkbench:
Image folderImg = PlatformUI.getWorkbench().getSharedImages().getImage(ISharedImages.IMG_OBJ_FOLDER);
For other common items (refresh, filter, collapse all, expand all), finding the images inside the plugins jars will be a tough task. So here are some images that you can reuse in your plugins:
Add, Delete : 
Collapse All/Expand All: 
Navigation: 
Window operations: 
Run & Debug: 
Import & Export: 
Date & Time: 
Editor Operations: 
Vertical & Horizontal: 
Flat & Hierarchical: 
Misc: Eclipse 
, Config 
& 
, Console 
, Font 
Help 
, Lock 
, Stop 
, Properties 
, Search 
& 
, Tip/Quick Fix 
, Sort 
, Task 
& 
, Sync 
& 
, Pulldown Menu
, Binary 
, Bookmark 
, Category 
Let me know if I've missed any commonly used icon. I'll add it to this list. The complete set of above icons can be downloaded from here.
Related:
Eclipse Icons - follow up post
Searching for Eclipse - source, blogs, images ...
Accessing CVS of Eclipse.org
If you are an early adopter of WTP like me, probably you would have gone thru the pain of downloading & installing all the prerequisites of WTP, that too for every milestone build. Of course, EPP has downloads for the milestone builds, but those are not enough. If you compare the versions, JEE version
doesn't have source, which I quite often refer for how-tos or as sample implementations of an extension point) and the RCP version
doesn't have JST. Recently I found that there is a bug already opened for providing all-in-one version for milestone builds, but its not been done because the PMC is not sure of how many people need it. If you are one of the guys who are in need of such build, do vote here.
Rest of us can download
the EPP's Milestone builds here.
