I guess I have a slightly different take on this. A basement that has
a history of flooding is a poor candidate to finish into anything,
regardless of what kind of floor you try to put down, without first
fixing whatever the problem is. I'd spend money on that before I did
anything else. And it's very unlikely just adding a sump pump is
going to fix it.

The major point of the water entry (say 98%) is from the basement
garage. The driveway slopes down into the basement for a one car
garage, so the only real water intrustion point is from the driveway
sending water under the garage door. The original drainage system was
a 1 inch deep trench that diverts water that comes under the door to
the side of the garage and foundation wall where the trench continues
for a few feet and empties into a drain in the floor. The floor drain
is well, about 80 years old, so needless to say, doesn't drain very
well. I think a sump pump installed in the current drain's position
and pumping the water into the back yard would fix the problem as the
water is not entering the basement through any of the other walls.
Basically, if I can stop the water at that one point, I shouldn't have
any future flooding problems (at least I hope).
Any other advise or recommendations on dealing with the water would be
appreciated though.
Thanks everyone,
David