While I do wish there was a "direct-from-device" import for Garmins, like others said, there are easy work-arounds. For the non-computer savvy like myself, I simply have a software program that syncs new files from my garmin to a directory on my computer. New files are moved to the GC library folder, then renamed from your-fit-file.fit to your_fit_file.fit and that's all it takes. GC will import those files automatically when it starts up.
The more gifted could easily script the whole process to copy the files, rename them, and launch GC when done.