24 f2.8 prime. I was hesitant on posting seeing as how I only have 1yr under my belt with a real camera and only have one other lens to compare it to- Zeiss 24-70 F4(rarely use). The 24 f2.8 really lends well to my favorite type of photography which is low light urban architecture/Storefronts/Murals.
I do alot of "walking" photography, so this lens pretty much lives on my camera. I rarely use the camera bag I bought with the camera. The size of this lens is a positive as well. I typically stuff the camera/lens in a winter stocking cap and that goes into a backpack with everything else needed.
Next camera purchase will be a 50 f1.8. I suspect I'll like that for all the reasons I favor the 24 f2.8 and then some. ZERO interest in a zoom lens.
HA, I did this last week except I think I have you beat- I probably took about 50 or so pics and got home to review them before I realized it.
My wife commented that this wont be the last time that happened. I responded with "nah, I make other mistakes, but I like to think I learn to not make the same one over and over". Sure enough, a few days brought the camera somewhere(remembered the card) and didnt realize till we got there that I had 17% battery remaining. I suppose my saving grace both times was that the camera was just along for the ride. We went to both destinations for other reasons, so travelled light.
My common mistakes in the year I've been shooting seriously-
No card
No battery/low battery
Hand in shot with smaller lenses
Leaving Exposure Composition on a value from the last photo session