On 31. May 2007, at 19:24, Cliff Pruitt wrote:
[...] I guess that most of the time I open a file, I'm opening a sibling to the file I'm currently editing [...]
[...] If you've already got a project open (re: "which is often in a subdirectory of the project") why not use the file drawer to just click the file?
Or even better: Navigation → Go to File… (⌘T)