If you've been thinking about getting Battlestar Galactica in HD DVD, don't. All signs indicate Blu-ray disc has won the high-def format war. The latest blow to HDDVD is Warner Bros. announcing that they will transition to being Blu-ray exclusive for their HD home video releases. (They have been format neutral until now.)
So, now only Paramount and Universal are exclusively supporting HD DVD. But with hardware sales and Blue-ray titles outselling HD DVD's, Paramount and Universal won't continue to lag behind. So, I'd just wait on getting Battlestar Galactica (or the original Star Trek) until they come out on Blu-ray disc.
For more info on the whole format war, check out The Digital Bits coverage.