Here's the thing about a 50mm... everyone says it's super cool to have as a prime (coupled with the rest of your zooms), but it's really too long to walk around with on a cropped sensor. A lot of people think this is a great indoor lens due to the aperture, but unless you're in a LARGE room, that's not really the case. Mostly good for portraits or very specific shots.
You should look into the Sigma 30mm 1.4. This will be much more versatile as an everyday lens. It's a newer design than Canon's 50 1.4, and has a great rep for image quality. There are many documented cases of front/back-focusing issues, but if you buy from a vendor like B&H with a strong return policy, that won't be an issue.
If you are set on getting a 50mm lens, I suggest borrowing a copy for a weekend first. This way you'll get an idea what you can and can't use it for.