There were three shirts we did that I absolutely loved..
The first had the greek letters on the front in white (black shirt) with a halo above them and wings flanking them and on the back it started with "it may be full of angels, but it's one HELL of a sorority!" and Pi Beta Phi spelled out in a font that looked like flames
We had a powderpuff football game against the Tri Delts (the only other sorority on our campus besides us) and they wanted panhellenic shirts. We decided against it and got red shirts w/ white letters and the front was the best: it had the PiPhi letters conforming to the shape of a football with the words "kicking ass" on the top of them and "since 1867" on the bottom of them....on the back was a football with wings and in the middle it said "powderpuff football game 2003"

here's a pic of the powderpuff ones sported by 2 of my sistahs!
Finally, we had shirts for the seniors. They were baby pink and said SENIORS in large letters across the front and IL Beta-Delta above it in small print and "Pi Beta Phi" below it in small print. On the back we had all the seniors names in a continuous line that made a graphic design...it was a wing and a halo....we had a rendition of the piphi pin on the back as well and the quote "we called each other a lot of things before we called each other sisters" I got a lot of compliments on it.