The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a long-term mutually monogamous relationship with a partner who has been tested and you know is uninfected.
JK, don't cover your eyes...
"consistent condom use is a highly effective means of preventing HIV transmission."
"Latex condoms, when used consistently and correctly, can reduce the risk of transmission of gonorrhea, chlamydia, and trichomoniasis."
"Genital ulcer diseases (genital herpes, syphilis, and chancroid)and HPV infections can occur in both male or female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered. Correct and consistent use of latex condoms can reduce the risk of genital herpes, syphilis, and chancroid only when the infected area or site of potential exposure is protected. While the effect of condoms in preventing human papillomavirus infection is unknown, condom use has been associated with a lower rate of cervical cancer, an HPV-associated disease."
Fact Sheet, Male Latex Condoms:
http://www.cdc.gov/hiv/pubs/facts/condoms.htm