I went for the 17-40mm f4, as I didn't do much low light stuff.
My advice would be if you aren't planning on moving to full frame soon go for the EF-S lens, you will get the wide aperture and the focal lengths you want. Don't compromise because you may go full frame at some point.
You really don't need ultra expensive equipment to get good pics just a willingness to experiment and try new things.
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