I change mine around depending on what I'm doing at the moment, but most often it's:
RPM ___
MPG TPS
... where the blank is typically LOD or FWT, sometimes GPH or IAT.
I have an analog tach and it works better than the ScanGauge for noting the shift from 3rd to 4th (automatic transmission) -- it's easy to see the needle drop with my peripheral vision. But my commute includes a stretch of road where the speed limit is 30MPH, and if I drive it
perfectly I can keep the car in 4th and get phenomenal mileage. The ScanGauge's digital RPM readout is much better than the analog tach for keeping the RPMs above the tricky threshold around 1575-1600 RPM where the tranny wants to downshift. (That puts me at about 35MPH, so it's a delicate balancing act.)
TPS because I'm trying different acceleration profiles to see which is most efficient, plus I know e.g. 10TPS reliably puts me around 1600RPM/40ishMPH/50ishMPG, etc. I like being able to accelerate to 4th gear and then quickly "lock" the throttle at what I know will be my final target.
Waitin' on the next rev of firmware so I can replace one of those gauges with current average MPGs.
Rick