Here are some external links to articles that illustrate many artifacts and approaches to mitigating them, collected together for reference:

De-interlacing with HQV high quality video processing (http://www.videsignline.com/showArticle.jhtml?articleID=171201964) - By Jed Deame, founder and engineering architect of Teranex, a unit of Silicon Optix

Motion Compensated De-Interlacing: The Key to the Digital Video Transition (http://www.siliconoptix.com/contentEngine/dspDocumentDownload.cfm?PCVID=27d27215-7e90-e2a3-b4ea-23fbc8689c4d) - By Jed Deame, founder and engineering architect of Teranex, a unit of Silicon Optix

De-interlacing video basics (http://www.videsignline.com/showArticle.jhtml?articleID=175006013) - By Mark Sauerwald, Gennum Corporation

Algolith Mosquito Video Noise Reducer Product Review (http://hometheaterhifi.com/volume_12_1/algolith-mosquito-video-noise-reducer-3-2005.html) - By Ofer LaOr

Video compression artifacts and MPEG noise reduction (http://www.videsignline.com/showArticle.jhtml?articleID=180207350) - By Phuc-Tue Le Dinh and Jacques Patry, Algolith

Deinterlacing with source, motion and edge-adaptive processing reduces artifacts on HDTVs (http://www.videsignline.com/showArticle.jhtml?articleID=202201435) - By C.H. Chee, co-founder and Vice President of Technology Marketing, Anchor Bay

Excellent reading; thank you very much for the links.:)

proud and humbled to be in such fine company...