As long as Windows XP is around and new raid drivers exist and can only be accessed by a floppy, the floppy interface will stick around a little while longer!
For an optical drive, pretty simple decision, get for the cheapest. That tends to be a drive with a PATA interface. As for being obsolete, would you trust a 3 year old dust sucking mechanical drive? I barely trust them when they are new. The drive will be junk long before it's interface will be considered obsolete!
Other issues are compatability issues with SATA optical drives that still exist, and why waste a perfectly good SATA slot on a slow assed optical drive!
Either interface should work though, you are not going to have painful regret picking one drive over the other, either will do the job.