String search: has Eclipse IDE got a modern "find" UI (a la Firefox)

Press ctrl+j. Is that what you want? Hold down shift to go backwards.

And, if Eclipse's incremental search is not enough, you could always use a plugin like Glance.
From their site:

Glance is an Eclipse plug-in providing extensible useful incremental text search in Eclipse. This plug-in supports the following features:

• highlight all found matches
  
• background search which never blocks text box
  
• search in tables and trees
  
• update matches when target content changed
  
• new text containers can be supported through extension points
  
• a lot of search settings

you can also select the word you want to search and use ctrl+K, use shift to go backwards.