Seems (lately) that about 40% of the time I put a CD or DVD into the disc drawer the disc isn't read and then the drawer won't respond to "open" commands unless I restart. Getting tedious - any thoughts?
Yes, Replace it. You can use pretty much any DVD drive from any brand and it will work. Just know that for an easy replacement, get an IDE drive as the 2008 models use IDE for the drive connection. Simple swap. If you want get a bluray drive, they only come in SATA, and while the mac pro has 2 extra SATA ports on the mother board, they could be difficult to reach, and you also need a power adapter to convert the original line to the SATA drive power connector. http://www.macsales.com sell a bluray kit that comes with all you need.