xargs is so 20th-century. parallel[0] is way more awesome (especially with all the multi-core systems everybody has now). Cool bonus: all the things you learn for xargs work in parallel too!
A billion times, this. I just learned of GNU Parallel about 3 months ago and wish everyone knew about it. Have seen it used to stunning effect with a comically large pipeline (OCR patents) across a comically large number of EC2 instances. Very awesome indeed.