All features more or less need a place to click to be launched. But restricting that clickable area to be toolbar buttons only, when there are so many great things to work with (using menus, dropdowns, split-buttons, checkboxes, navigation, pages, dialogs, context-menus, keyboard shortcuts, ...), would inevitably create a cluttered toolbar.
Exactly which buttons that will be used and which that should go away or become something else is indeed a difficult task to sort out to start with. And after a couple of releases with functionality added, I promise the toolbar can become a Frankenstien's Monster of functionality. You are doing yourself and your clients a favor never letting it. :)
You can never make a toolbar from where all tasks are done. Structure and navigation is key to not only keep "everything at your fingertips", but also keeping the UI "clear" (a thought on that on Google IO 10).
The toolbar in the top of a window/page is typically for actions that are frequent or applies to the state of the entire window/page. Other actions are more conveniently placed next to what they affect, and some do not fit on that page at all, but should be found when navigating away to another page/dialog/window, typically viewing a record or returning to the results, which have its own actions and toolbar.
It is hard to say what you could do without more information about your context and design so far, but based on the examples you provided about [return to search], a button on one page should inmho simply not manipulate the content on another. For minimum confusion, the action that applies to a content should visually be placed next to that content, so that the user can see what the button does when clicking it.
One of them must be the typical thing to do considering the work flow, and I guess that it is returning to the search results the way they were when we left them. The other option should be a click away from the search result list, not from the viewed record itself.
There is just so much a user can focus on, at a time, anyway.