With all the good news coming out in favor of bitcoin like
Expedia accepting bitcoin etc it's time to buy with the price going down. You will not be so lucky next week. I strongly believe it's going to reach $700 by end of next week!
Today is the best time to buy because as we noticed that the price is still low and looks like it will increase on the latter part of the year. Since the price is low, just buy now and hold until the price will rise up soon.