"Let me continue with Konqueror. Search bar (comes with kdeaddons package) now has the possibility to select the desired search engine from a dropdown menu similar to the one in Firefox. To select which engines are available in the menu you simply put a check mark before its name in the Web Shortcuts settings dialog.
"During the past two weeks a new del.icio.us bookmarks panel made into KDE 3.5. del.icio.us is a special online social bookmarks managing system and now you can do many of the tasks directly from within Konqueror..."