As with any marketing activity, best results are obtained when doing something with your business or postcards that is outside the norm.
Think about it: you see plain-jane business cards every day. Same with resumes.
Just as a quick and easy way to set your resume apart is to use a splash of color print on color, higher-quality paper, so too will your business cards be set apart by a splash of style.
Here's some links for inspiration:
Cool business card designs | creativebits
Cool business card designs, Part 2 | creativebits
» Creative Business Cards