As i can recall:
for Straight in approach: You shot the approach without doing a reversal procedure. If you have an aircraft with FMC you can go straight to FAF.
Straight in landing: is a term used when the final approach course is withing 30 degrees of the runway ( as most of the FAC are).
Visual approach: Is a visual manouver where you MUST have the airport or the preceding aircraft in sight at all time. You are responsibel for maintain clearence to terrain.