Thanks mods (again) for reopening this thread!
Wanted to mention that I did some spotting at the Proud Bird this past Sunday (along with a couple other guys).
TLDR: Same as In'n'Out but on South Side looking north.
Long Story:
So first off, if you haven't been to the new Proud Bird, it is completely different. It's not a sit-down restaurant anymore; it's more of a food court type setup, along with a bar. Actually sort of feels like the food court area in an airport terminal. It's bright, airy, and has some aviation-related displays. There is an outdoor eating/drinking area as well, with great views of 25L/R arrivals.
That said, we didn't actually get any food or drink. Rather, we parked around in back, and hung out in the adjacent field (where they have the display aircraft) just north of the building. There were others hanging out there, and there were a few people sitting on lawn chairs in the back parking lot. So seems like it's no big deal for people to just spot from there, but it would be a great place to get some food or a beer whilst doing so (not sure on prices though).
Note that you will be to the south of the airplanes (looking north), so this spot is best during winter, and decent-to-good during fall and spring. A 70-200 or 70-300 lens ought to be perfect. I was using my 100-400, and that was mostly fine, but 100mm was too long for larger airplanes at their closest approach.
Couple examples:
(I'm so used to typing "Approaching 24R" that it required a whole brain re-wiring to start typing "Approaching 25L")