Meaning regular sets when saying straight sets...I believe.
Time is also another element, that can be very import in any progressive overload system, that most may overlook. How much work (tonnage moved/lifted) is actually performs in a given amount of time, on any exercise. Setting up a fairly fast pace, within workouts, can excel muscle growth, and has, for quite a few..
Here's where TUT (Time Under Tension) comes into play. Short breaks between sets or methods like One & one Half's (which Wes mentioned in another thread), 7's, tri set, ect. I somewhat favor quad sets, either SS'ed (with opposing muscle contractions) or working the same muscle for the whole 4 sets. Quad sets are like a shorter version of Giant sets, which can also be a good structure for a higher end workout.
Keeping it simple, for the moment: might suggest a couple of methods that come to mind. 10X10's (GVT) and 8X8's. Using the same moderate weight throughout all the total sets. May seem easy at first, but becomes very demanding after working into it.Time becomes an element here also. I have used squats, DL's, pullovers & press, for excellent results with the GVT version. Good Luck.