I really like these videos from SIGMA lately showing off the features of their new lenses.
These are nice videos from SIGMA. One more after the jump.
Pricey, yes, but the Sigma 50mm f/1.4 DG HSM ART lens has gotten a superb 92% rating on DPReview. That puts it up there with other high-performance 50mm contenders at a much more affordable price (though still a bit expensive).