When I have multiple files open in Eclipse, I often use Ctrl+PgUp/Ctrl+PgDn to cycle through them. But the thing that always makes me lapse into pirate-speak is when one of the files in the middle is an XML file.
The Eclipse XML editor has two sub-tabs of its own: a Design view and a Source view. When the current editor is an XML editor and I Ctrl+PgDn, instead of going to the next editor, I now go back and forth between the Design and Source views of the XML file. Arrrh!
Since I never use the XML Design view (I wish I could hide that tab), I also generally press Ctrl+PgDn one more time to get it back to the Source view first. Then, to go on to the next editor, I have to either reach over and click with the mouse or press Ctrl+F6 instead. Either of these alternatives results in a break of flow, but Ctrl+F6 is the worse one: where Ctrl+PgDn moves to the next editor as soon as PgDn is pressed, Ctrl+F6 (and its twin, Ctrl+Shift+F6) pops up a list of editors when the F6 is pressed and then only goes to the selected editor when Ctrl is released. These differences can be enough to break the flow of thought so that I forget what I was doing and have to stop and regain that focus.
It turns out that this issue was discussed on the eclipse IRC on February 15, 2008 (follow the conversation starting with eidolon at [16:13:25]), and that Eclipse Bug 199499, Switching tabs by Ctrl+PageUp/PageDown must not be caught on the inner tab set, has been logged for this issue. I added my vote!