what you may be thinking is DVD-r.
And or CDs (CD-r)
Some of the first Sony Blu-Ray players had lots of trouble playing those formats, downright NOT playing them.
Blu-Ray in general is regional coded, HD DVD is not.
As for the difference in the HD PQ, there is little difference, choose what movies you like.
As for a locked standard, everything should work, go with HD DVD.
As for what has the potential (years later) for better quality, then go Blu-Ray.
Hope that did not confuse more....