I usually used a 30mm F1.4, or 35mm F1.8, on APS-C crop bodies for many years. Recently picked up a 16mm F1.4, and after trying it out in Dec and Jan on Disney trips, found I much prefer the wider perspective it provides in tight dark ride conditions, so going forward this will likely be my go-to lens (still on APS-C). I still sometimes use the 35mm F1.4 when I want to go in tighter for some details.