Weeeeeell, that depends. You don't need to get SP1 in order to be functional. However, in order to have everything working, you'll need it. For example, USB 2.0 support won't be enabled without SP1. You'll still be able to use the ports in 1.1 fashion without the service pack, but 2.0 won't be available.
At any rate, it's best to install SP1 unless you have some grave reservations about it.