go to the ">>" window to see which file I'm currently working in, rather than just looking at the top and seeing which one is the 'clear white' tab.
Unless I'm living in a parallel dimension, the name of the currently viewed file is always at the very top of the window, next to the file icon above the tab bar. Is this not the case?
Command + T (Go To File) is also your friend, as is Command + Option + (L/R) Arrow (Go to Previous/Next Tab, respectively).
~ Daniel