Yet another user is interested in
Fedora Electronic Lab.
This one is eager to switch to Fedora from Ubuntu Feisty if Fedora can provide him tools to read his OriginLab PRO 7.5 project files. He pointed to the fact that on Ubuntu Feisty, LabPlot crashes while importing his OriginLab OPJ project files. Actually on Launchpad there
is an open confirmed bug on LabPlot since February 2007.
For some reason Fedora's LabPlot does NOT crash on importing OriginLab OPJ project files. I've tested on i386 while kwizart did on x86_64. Well what's our trade secret ? We don't have any, if I remembered, except we are using system wide libraries during the build process.
Case study:
Either create an OriginLab PRO 7.5 project on windows:

Save the project.
or grab a copy from
here.
# yum install LabPlot
on LabPlot : File -> Import OPJ Project (that's it)

Now that I've explained how to import data from OriginLab to LabPlot, one can also import their data from LabPlot to OriginLab. On LabPlot : Spreadsheet -> Export data. Save the data in a .dat file. Then use OriginLab to import that .dat file.
If one is using OriginLab in the past, he/she would be happy with LabPlot as it has sufficient features to compete with OriginLab. LabPlot on stable FC6 and F-7 does NOT crash.