Which mode should I use? Up to 54, 150, or 300 Mbps?

I have a Netgear wnr2000v3 router and it gives me options for these modes: up to 54, 150, and 300 Mbps. My question is which one is best or is there any difference between them. I mostly use the internet on my laptop to watch movies on Netflix, and download small and large files. It is currently set to 54 Mbps because I figured since I am paying for 12 Mbps and my laptop's wireless card only supports up to 54 Mbps there is no need to set it to 150 or higher. Am I correct?