This sounds like a picky nit, I know, but I think
the x-icon on the editor tabs that is used to
close the file is too small.

I frequently find that if I'm not very careful
with my mouse cursor when I try to click this
button, I actually miss it and the file doesn't
get closed.

By contrast, the x close icon on Netbeans windows
is significantly larger and much easier to select.

I know this tab area is very valuable real estate.
However, Eclipse tabs have a much larger close
icon (also an x) in the editor tabs and I find
it much easier to close windows. I definitely
don't find the larger icon in Eclipse 
objectionable.