P.S. — I love seeing everyone interact with each other here, so I am also going approve comments without replying (with the intention of still replying personally!) as I can so that you can see each others comments ASAP!
For sure, Guerlain Parure Gold when I look at an “all time” record! Following that, I wore MAC Studio Fix Fluid for at least a couple of years long ago. Currently, Tarte Rainforest of the Sea has been my go-to since it debuted, and I don’t expect to give it up any time soon!
I don’t know if I’ve found the perfect one myself, as I am pretty terrible at staying true to one for long (I just fall off… I can moisturizer nightly, but the extra step of serum I’m not-so-good at!). Looking for recs for drier skin types (that’s what I’d want a serum for). The one that I have liked and used more routinely was Ole Henriksen’s Vitamin C serum.