Xcode 4 adopts the same sort of single-window workspace that Visual Studio has. I personally hate it and think multiple windows are much more productive, but if a single window is what you want, you'll like that aspect of Xcode. The integration with gdb is a little sketchy. Fortunately, Apple's been working on a replacement called LLDB for a while, and while it's not quite there yet either (it's currently pretty buggy, and is not the default debugger yet for that reason), progress on it has been pretty swift, so the situation is probably going to get better in the next few versions.