At least for currently visible top node, if you modify your "Custom Node Title Definition" in Display Settings, you can add the following: "%T: %N" (as I do), so that whatever node you're looking at will display its name and title in your browser's title bar (and in my case, in the page's Firefox tab)
If I have multiple Firefox tabs pointing to multiple pages, each tab will have the node name, and the node ID displayed on the tab itself. Very handy! If I'm discussing several nodes in one of my posts, I usually just open those nodes in separate tabs so that I can quickly see the node ID's.
Available tokens are %T (title), %D (create date), %N (node id), and %S (section; e.g. SOPW, Q&A, but only for root nodes).