The new Xbox Live family pack is a great idea. Just be aware if you have existing Gamertags to add, you can only do that through a console (currently). You need to have all the profiles on the same console (temporarily; just a memory stick will do). Don’t be tempted to “Create Family Member” through the Family Center page at http://www.xbox.com :). Doing so will create new Gold accounts, which count against an annual add/remove limit on the pack. These don’t expire for a year 😦 The unfortunate solution is to cancel your Family Pack (which seems to temporarily return the accounts to Silver/Free status – ugh 😦 ), then re-buy it (making sure you chase up any remaining-time credit you may “lose” in the process).
Other than that, $99/year for 4 Gold accounts is a nice deal 🙂
Update 1: Canceling the pack isn’t a sure fix 😦 (they’re looking into it 🙂 ).
Update 2: Others with same issue – http://forums.xbox.com/34945194/ShowPost.aspx#34945194