Most every panel manufacturer makes their own that can be plugged onto the bus bars of their panel.
For the money, I usually use Delta brand. Their arrestor uses silicon oxide instead of the metal oxide varistors.
There are other technologies available, some of which are sophisticated and expensive. Visit http://www.powerquality.com/
check out the back issues for more on this topic.
Don't forget that the arrestor at the service is only part of the solution, point of us supressors are also needed for complete protection.