You'll need a very very fine grained film to go that large in black and white if you want the prints to be really sharp at a minimal viewing distance.
In black and white, the top of my list would be Adox ORT 25, available from Freestyle Photographic.
Beyond that, Efke/Adox 25 or Ilford PanF.
In color, Velvia 50 or Astia. Maybe. Maybe. You'd have to have them drum scanned.