You may decide to give only to your biggest clients and perhaps to those who have helped you in key areas. You may also want to include people who have referred business to you. Appropriate gifts are not controversial, too personal or excessively expensive. Cash is a no good since it might be misconstrued as a bribe. However, gift certificates may be just fine.
Meaningful gifts are the best kind, so base gifts on client interests whenever possible.
If you are buying a gift for a team of people, rather than one person, send something that can be shared easily. For the past two years, I have done a lot of my shopping online. This season many e-vendors are offering free shipping, extra discounts and free products with purchase. If you own an online business, I recommend shopping almost exclusively through the Internet. By practicing what you preach, you send an important message.