Since I didn't want to schlep bags all around Gare du Nord to transfer from the RER to a regular Metro line and again from my station to my hotel, but didn't want to drop 50 Euros on a taxi, I chose to take the RER B from CDG to Gare du Nord, then just exited there and took a taxi straight to my hotel. In my case it was 7.50 to to Vendome, but I would have done it even staying a bit farther away. Within Paris, taxis are not exorbitant, so it's a good option when Metro doesn't suit.