Check out the latest tutorial: How To Edit GoPro HD Videos - A Complete Workflow
A frequent problem all GoPro HD users have is finding the suitable video editing software that will both import and export in HD. The video output of the new action camera is MP4 with H.264 encoding which is a standard for digital video, remarkable for it's high compression rate.
Since I don't have a Mac laptop I can't speak for that but for the PC (Windows) users this information might be useful.
So if you're a Windows guy then you may have noticed that Movie Maker doesn't even import the MP4 clips form your camera. What you can do is convert the files into a more common format that will be then importable by almost any video editor. The bad part here is you'll loose the original HD quality of the video and then I may ask: What's the point of paying more for a HD camera if you can't show your edited footage in full quality?!
I tried lots of programs, looking for one that will run smoothly on my Dell Inspiron 1525 laptop.
To this point, the following video editors failed: Adobe Premiere, Avid Media Composer, Pinnacle Studio, Ulead Video Studio Pro, Pinnacle Video Spin. Some of them can do the job but they need a much powerful computer than I have so they're useless for the amateur editor - who's main focus is doing crazy stuff outdoors not buying expensive computer hardware, not to mention the software (at least 500$ for Adobe or Avid).
Don't get me wrong - Avid and Adobe create world class software but their creations just didn't run well enough on my computer. Within the editor's playback window, the footage played like a photo-stills slide show thus I couldn't see exactly were the scenes began.
Ulead impressed me with its stability but unfortunately it doesn't import MP4 in H.264 encoding. You can see the
.mp4 option in the File Import window but if you try to import your GoPro HD clips you will get a message like "File format mismatch" - see screen capture below.

My relief came with
Magix Movie Edit Pro Plus 15, a software that I've learned about by reading comments on other outdoor blogs. Movie Edit Pro imports MP4 and exports it in HD just as you'd expect!
I had to go through my learning curve with this product as well and now I'm happy to see the results. At first I wasn't able to edit clips longer than 1 minute as I got a message referring to "not enough memory" - 2 GB RAM that is and a Core 2 Duo Intel processor at 2 GHz. Then I came to the conclusion that the source files should have been downloaded on a bigger partition on the hard drive. As I dragged multiple clips into my project and also made a lot of cutting, the video editor was creating temporary files which were saved within the same folder as the source footage. So all those files were slowing down my computer until I eventually ran out of space and consequently out of computing power.
Now I download all the clips on a partition where I have at least 50 GB free space available and I also make sure the project folder contains the source files.
Being able to export in HD using a medium computer makes it a great software to work with and all this comes at a fairly good price - 89$. The interface is as intuitive as it can be so you won't really need to go trough tutorials in order to edit your clips - at least for basic editing you'll be fine with
trial and error.
I also wrote a few mails to their support team and they always replied fast and with valuable information. If you want to have a true experience I recommend you download the free trial and test it yourself.
Other recommendations for editing your videos can be found
here - Computerworld.com article.
Cliff Jumping in Bulgaria - Edited with Magix Movie Edit Pro Plus
Cheers!