I ship DVDs through the mail and through UPS. No problems with boxes and bubblewrap. UPS also has a disk mailer made specifically for overnighting disks.
I also prefer priority mail. Its cheaper than the alternative, delivery in two days, and you get a delivery confirmation.
I use bubblepack all the time, with the DVD in a case. With a thin jewell case, the entire package takes two extra stamps, which comes to $0.95 in postage.