Matt S. gives us an awesome breakdown of the Canon 50mm F/1.8 vs. the Canon 50mm F/1.4.
For anyone that's ever purchased their very first Digital SLR and has asked me what lens they should buy, i've always sworn by the Canon 50mm. Depending on how cheap that person is determined whether or not they started out with the 1.8 or the 1.4 version. (I started with the 1.8 version - i'm cheap).
The Canon 50mm F/1.8 lens Found Here for less than $99.00 dollars, is the cheapest prime you can get into that gets you shooting some very professional looking images. It also feels like the cheapest.
The Canon 50mm F/1.4 is about 3 times the price at $349.00 Found Here, and adds some worthy features like a bigger smoother focus ring, more quality build, and an aperture of 1.4. Check out the video above to get more information, and If you're not an owner of either Canon 50mm's, well you're just hurting yourself....Get one!
There is also a F/1.2 L version, but we'll save that review for another day. Check out the Price on the F/1.2 version