How about the FD 24mm f/2.0? Got one and like it a lot. Can be had for quite a bit less than the huge 1.4 version.
Great lens. Very sharp. 24mm f1.4 L (or, even better older Aspherical) is great, too - not so sharp, but faster... I have both.
More great FD primes I recommend are (and I have almost every Canon FD lens ever released up to 200mm):
35mm f2.0 (compact, quite sharp, useful focal length for 4/3 but beware of the radioactive version - it's sharper and better for b&w stills, but your footage will have orange cast)
50mm f1.4 (cheap and great), but I love my 55mm f1.2 Aspherical, too (heavy piece of glass, though)
85mm f1.2L or (cheaper and lighter) 1.8
135 f2.0 is amazing, too, but you won't use it on 4/3 too much.
I'm yet to find wideangle lens to match my FDs set well. My 20mm f2.8 becomes ~40, which is not as wide as I'd like to go sometimes