It took me 12 hours to build X11 on my K3, using arm debian build tools in a debian chroot. Using crosstools on a host PC would be MUCH faster.
I successfully installed win32 CodeSourcery GCC inside the win32 CodeBlocks IDE on my WinXP VM, and I also sometimes use linux CodeSourcery GCC inside the linux CodeBlocks IDE.
In linux, I find it easier to just use gcc (or make) from the command line. But in windows, I like using CodeBlocks better. CodeBlocks supports editing (with syntax highlighting and code folding), compiling without leaving the editor, and debugging (breakpoints and single-stepping through the source code). Clicking error messages takes you right to the offending line in the editor. Nice!