I got another subscription back in July even though i knew 360 was just around the corner because I felt it was not unrealistic to assume the price would rise.
I understand that the live kit over in the US is $59 currently, but is going to be $69 witht he launch of 360, so perhaps you should get another sub now. As Acert said, you can carry it over, so why not? I guess since you'd almost certainly be getting the premium pack, you'll get a headset with that and will therefore only need to pay $59 for the gold sub for a year, so no difference at that point.