Over the years I've seen 3 different ways to trim (or clip) curves. The first I ever learned is pictured above - cut little triangles into the seam allowance.
In one of the classes I've taken at the Original Sewing & Quilt Expo over the years (and I'm sorry I can't remember which one), the teacher showed us the technique of cutting diagonal slashes into the seam allowance - the trick being to cut each side of the seam allowance separately and from the opposite angle - so that the slashes oppose each other. (Hopefully that makes sense.)
Recently, I used a pattern that illustrated the curve slashing with a lot of little snips that were directly perpendicular to the seam.
So, how do you trim your curves? Do you think it matters much, or do you think any of these methods would be equally good?