Best gui for remote gdb

I recommend trying out Qt Creator. It's cross-platform, has pretty good "code insight" features, and is a hell of a lot lighter-weight than Eclipse. It is a full IDE, not just a debugger front-end. It does require a gdb built with python support (client only, I think), but does come with it in its cross-platform installer. It is definitely more geared to developing C++/Qt applications, but does support generic Makefile and CMake projects, and I use it as my everyday C IDE and debugger.

Depending on exactly what kind of remote target you're debugging, the answer to this question could vary a lot. If you're cross-debugging to a deeply embedded microcontroller target running an RTOS, your options are going to be more limited.

For Makefile-based projects, you want to use the "Generic Project" creation wizard, which by default adds all the source files under the specified directory to your project. It may take some manual work to maintain your project, if you want Qt Creator to "understand" things that you've specified in your Makefile like command-line include directories (go in your .includes file), command-line included headers (go in your .config file), and command-line symbol definitions (go in your .config file). The project file list and compile, deploy, and run commands can all be maintained from the GUI though.

I'd recommend eclipse Indigo it has built-in support for remote debugging applications via gdbserver. I just don't know where the source code has to be located for it to work.

Sinec it uses the MI interface of gdb it should work as any other interface that interacts with gdb.