Which Prime?

Thanks to everyone that replied. You've all given some valuable information that I'll use in making my choice. As of now, I think it's going to be between the Canon 28 f/1.8 and Sigma 30 f/1.4. Right now, I'm leaning towards the Canon 28 due to it being smaller and lighter, a tad wider, and the fact that it will work on both full frame and crop. I'd like to go full frame at some point, but I think that I'm still a few years away and would really like to not have to replace the lens if I enjoy it as much as I hope I will. Thanks again to everyone!

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Life is tough, but it's tougher if you're stupid.

-John Wayne as Sgt. Stryker in Sands Of Iwo Jima