Most would probably say RetroArch and Higan. RetroArch for the ultra low (better than actual consoles) latency, and Higan for the accuracy.
I'm more old school and prefer standalone emulators, and also not a fan of the clusterfuck that is the RetroArch interface with all its various settings. And my laptop is also getting a bit old so Higan would probably not run great anyway.
I still use Project64 2.x for N64 stuff (with GLideN64 when my laptop actually runs it well - for some games I have to resort to Glide64 or even Rice Video)
VBA-M for GB/GBC/GBA, I just like the feature set and I'm used to the interface and it works perfectly for the things I use it for so why fix what's not broken, right?
Snes9x for SNES... Was still using ZSnes several years ago actually but was tired of how it didn't run Bubsy due to a regression and I had to revert it to a really old version just to make that game run so I thought fuck it, not worth the effort.
And ePSXe for PSX games. It's still the best thing around for PSX as far as I know, with the right plugins.
For PS2 and GC/Wii you don't really have much choice, PCSX2 and Dolphin are the only ones I know of for PC and while there probably are other ones I doubt they work very well.
Occasionally I load up a Sega Genesis/CD/32X game, usually in Kega Fusion because it has an xBRZ filter.
Other consoles I don't emulate much but I still have a bunch of other emulators around.
My emu folder currently looks like this and it is a bit of a mess with some old stuff I haven't bothered to get rid of yet, and some stuff that just hasn't been used (or hence updated) in ages, and for some of the consoles I am not actually sure which emulator is the best that's why I have multiple for Dreamcast and Saturn, among others:
https://www.dropbox.com/s/i6a7f015m445bj9/Screenshot 2019-11-13 00.50.52.png?dl=0
My post doesn't really answer the question in the OP at all though if someone has suggestions for what would be better alternatives for some of these feel free to tell me
Saturn is especially problematic, Yabause had pretty poor compatibility last I checked and SSF is closed source and has its fair share of issues too.