Hi , so I was set on the Nikon 50mm f1.8 because it's sharp and works well in low light but my friend recommends the 35mm f1.8 instead! He says , because I'm using a Nikon D80 ,which has a 1.5x crop factor , the 50mm will become a 75mm. So I'm wondering , do the numbers really matter? Is a 75mm bad? Why would a 35mm be better than a 50mm? Reasons I want the 50mm , as I said above , is image quality and allows for low light. I also don't mind a prime lens instead of my current 18-55. In fact , I rather have a prime lens on the camera more than the 18-55. Also , the 50mm is '' cheap and good '' but the 35mm is almost double the price , which makes me lean toward the 50 but more importantly , which would be better for me? Lastly , which of these lenses would be better for street and walking-around photography? Thanks!