What is the effect on ones credit with bankruptcy versus foreclousure on a primary residence?

Both will do bad things to your credit scores. The BK will remain on your credit report for 10 years; the foreclosure for 7. Agencies such as FHA and VA will allow you to be eligible (not necessarily approved) for a new mortgage 24 months after the discharge of a Chapter 7 BK, and 36 months after a foreclosure. If you chose the BK, be sure to pull your credit from ALL three bureaus about 90 days after the discharge to make sure that ALL items discharged are shown as such. Any items that are not shown as "Discharged in Bankruptcy" should be disputed by checking the box Discharged in BK. This will enable your scores to recover quicker.