Other than my badges, my most prized SAI/Phi Sig stuff is-
My SAI bid card which I had beautifully framed with red and white in a very pretty black frame. It hangs above my desk so I can oogle at it ever day.

Then again, when I went to headquaters two weeks ago and got a personal tour from Ruth Johson, she gave me a bunch of SAI stuff. So, maybe the picture I have of her and I singing the choral is a close second. And, there's also my SAI scrapbook.....gosh, too many choices!
My Phi Sig initiation folder is the most prized phi sig posession I have. Finishing that damn folder was quite the achievement. I will NEVER throw it away. But, then again, I do have my phi sig scrapbook that I love also. Over the weekend, I plan on doing a "Toga Party" page.