AFAIK, QuickDraw was never a graphics
format, it was the graphics
technology used by Macs from day 1. Do you mean that you have some old PICT files? If so, they should be able to be opened by Preview, and you could do mass conversions with something like GraphicConverter. If you're unable to open them, it's probably because they are so old they don't have an extension (.pict), so they aren't being recognized by modern tools.
If they're not PICT files, can you give us more info on what software created these files?
As to a good file format for the future, there's no way to pick one specific format and say that it will still be in common use in 10-20 years... but something like TIFF would probably be a reasonable choice for lossless storage, and high-quality JPEG will probably be good for a long time, but is lossy, so some of the photo data will be thrown away.
