One thing I miss when filming in sd mode is avi files show up as picture thumbnails. Now with M2t files they do not show up as pictures. If i was to purchase either gearshift or neoscene will thumbnail pictures then show up in folders? Or what can I do?
Thanks in advance.

Install Windows 7 RC. It shows AVCHD and m2t files as thumbnails. It might, however, be to late to download Win 7, I'm not sure.

Will any HD extension show up in Windows XP?

If you mean will they show up as thumbnails, definitely not natively. I don't know if you can even get them to show up as thumbnails in Vista, but I could be wrong. I never was able to get HD thumbnails in Vista. I haven't used XP for so long I don't even remember what it looked like! Sorry I couldn't be of more help.

Will any HD extension show up in Windows XP?

I've got several different HD samples on my computer and the only ones that have proper thumbnails are the clips from a Nikon D90 as they're AVI files.