I got a box of Foma100 in 4x5 the other day, just to try it out. I've also scored some boxes of 4x5 Plus-X Pan that I'm hanging out to try too.

But none of that today, I'm off to Canberra for a few days tonight, packing:
Mamiya 645AF, P67 45/4, 80/1.9N, trying Ektar100 for the first time. (along with Delta3200 for indoor pub shots, Efke25 and PanF50 for outdoors, and some Velvia50 for the hell of it)
Bessa L with 21/4, also trying Ektar 100 for the first time in 135-size (and more rolls of Velvia).
Bessa R3A with 40/1.4 Nokton and 90/3.5 ApoLanthar, and a few rolls of Tri-X 400.

Mostly I'm interested in comparing the Ektar and Velvia, although it won't be completely side-by-side, it should give me a nice indication of what Ektar is capable of...