Appearance, engagement, and media are factors students use in judging the quality of an online course and the credibility of the instructor. While you don't need to be a computer programmer or artist, you should take efforts to find and use interesting, attractive, and engaging materials in your course designs. There are many great tools available for free or very little cost which will allow you to quickly and easily develop your own materials as well.
You've heard it hundreds of times... "Don't reinvent the wheel."
Agreed! Reinflate it!
A great strategy for incorporating media into your course sites is to locate and link to existing media and learning objects already available.
I would suggest starting at Merlot.
http://www.merlot.org/ - Multimedia Educational Resource for Learning and Online Teaching (MERLOT) is a "search engine" for finding learning objects (which can be used at little or no cost). The site offers peer reviews and opportunities to network with colleagues.
Other very useful sites to "reinflate" are:
http://ocw.mit.edu/index.html - MIT Open Courseware
http://www.pbs.org/teachersource/ - PBS Teacher Source
http://www.learner.org/ - Annenberg Foundation (K-12 programming through Satellite and Video On Demand)
More sites for learning objects to check out:
http://www.lolaexchange.org/
http://ali.apple.com/ali/resources.shtml
http://careo.ucalgary.ca/cgi-bin/WebObjects/CAREO.woa/
http://cnx.org/
http://ideas.wisconsin.edu/videoideas.cfm - includes library of videos
Index of Learning Object Collections
http://www.uwm.edu/Dept/CIE/AOP/LO_collections.html
Reviewing what others are using and creating not only provides you with a ready source of content, but it also helps you design better materials from scratch.
There are some really great resources, some "okay" resources, and some that are not very well produced. Investigate and thoroughly "test" before offering anyone else's work to your students.