I love 160 in my Holgas and it's my favorite film right now.
I have also had good results with Ektar 100.
It's very bright where I live so I can easily get by with 100 speed.
For black and white, I think the best results (for me) are with 400 speed.
Every Holga is different though, so keep that in mind.
Even the shutter speeds vary between cameras, so your best bet is to waste some film and keep notes if you're the note taking sort and see what's best for your camera.
My newer Holga is about F/13, but my first Holga from the late 90's is about f/8 since I modified it and knocked out that small inner ring in that cone/pyramid shaped lens holder inside of it.
Good luck! I'm anxious to see what you do with it!!!!