I updated Eclipse with the new SDK tools (rev. 23), but now when Eclipse starts I receive the error:
This Android SDK requires Android Developer Toolk
What I have just found is that you need to update your ADT plugin in your Eclipse (whether stand alone or ADT Bundle) before updating your build tool.
If your Eclipse installation points to the most recent Build Tool and your Eclipse is having ADT 22.x, it will show those errors.
What worked for me: (on Ubuntu 14.04 64-bit)
You may not have an older copy of Eclipse and Build tools, in that case you can uninstall latest build tool from SDK Manager and install the older copy.
Once everything starts working fine, do the above steps.
I am trying to upload older copies of such bundles somewhere on the Internet, will update the links here, once I am done uploading.