I never have any problems with this regimen: clean after use, sanitize before use.
Cleaning means removing all visible contents from the tubing. Usually running some water through suffices, sometimes I need B-Brite or something. Whatever happens, getting dried gunk out of tubes is a bitch.
Sanitizing means actually murdering all the little abominations, whether on surfaces or in tubes, that want to jump into my beer. For this I have used Star San and bleach to great effect. I'm sure iodophor is fine too. I always run water through after sanitizing too, but with most sanitizers I don't suppose you have to.
Frankly, I feel like sanitizing after use is a waste of time since I feel that anything coming in contact with beer should be sanitized before use immediately before use. A sanitary surface eventually becomes an ideal surface for our local microflora or microfauna. I wouldn't feel comfortable depending on the results of a sanitation I did weeks or months before.