If you need/want more than 2 simultaneous netflix streams you will need to pay for one of the higher disc plans. The 3 disc plan will get your 3 simultaneous streams, and the 4+ disc plans are all capped at 4 simultaneous streams according to the netflix faq:http://www.netflix.com/Help?action=2&js ... multaneous
Can I watch movies instantly on more than one PC or Netflix-ready device?
Some membership plans allow you to watch simultaneously on more than one personal computer or Netflix-ready device. If you are on the Watch Instantly Unlimited plan or the 1-disc-out-at-a-time plan, you may watch only one device at a time. If you are on the 2-discs-out-at-a-time plan, you may watch on up to two devices at a time. Members on the 3-disc plan can watch on up to three devices. The maximum is four devices -- available for members on the 4-or-greater-discs-out-at-a-time plan.
Your account can have up to six unique authorized devices activated (and associated with it) at any given time, including personal computers and Netflix-ready devices. For example, if you're on the 1-disc plan, you can have up to six devices associated with your account, but you can only watch one of them at a time. If you're on the 2-disc plan, you can have up to six devices activated but can only watch two of them at the same time.
Note that although the FAQ states only one stream for the one disc plan, Netflix has allowed 2 streams for a number of years now. I have never found anything official about the streaming only netflix plan, but the assumption is that it functions just like the 1-disc plan in regards to simultaneous streams.