TiRed, I’ve had the 35mm version of that lens for 25 years, first on my FE then on half a dozen DSLRs until my D800 now. If I’m going for a wander, that’s the lens I put on. Such a characterful lens. If I’ve coat pockets or a bag, I’ll carry a 50mm f1.8; but often it’ll come back unused. I persevered when it went from SLR to cropped DSLR (D70s!) and I did use the 50mm a lot when I first got a full-frame sensor, but the Nikkor didn’t take long to get reaccustomed to. If I want lens versatility, autofocus and pin sharpness, I’ve a 24-70 f2.8. Excellent kit, but feels a touch sterile at times.
For a crop sensor, a 24mm or 35mm would probably be my choice if I was limited to a single lens. Around 35-50mm in ‘real’ terms and good for pretty much anything. Not sure that would change if the budget was unlimited, I’d just go for the f1.4 version. That said, if my budget is unlimited I’d probably not be using a crop.