Lowering basement.

Hello - I have an unfinished basement in a new home that I would like to finish. The basement is 700 SF, has a walk-out entrance, is ~3' below ground level on average, has dirt floors, ~8.5' ceilings, rough framing, and is next to a crawl space (which is covered w/ a black moisture barrier). There is a 1-way drain @ floor level that drains to the street. *My question is as follows: What are my flooring options? - Do I need to pour a concrete floor prior to putting in a subfloor? - Could I use gravel/vapor barrier, press treated joists to form a subfloor? Thank you.

I live in a 75 year old house & am having a problem with water entering the rear wall of my house into the basement. A surface draining system has been installed in the yard which helps quite a bit but I still get a wet floor after a heavy rain. The basement is finished, but luckily the floor has easily removable carpet tiles. I also have a low cedar deck (about 1 foot off the ground) in the rear yard adjoining the house where the water is entering. My drainage contractor is recommending removing some of the decking boards & installing a sump pump under the deck with a couple of french drain arms off of it. There are built-in storage cabinets inside the basement against the back wall so doing anything on the interior would be problematic. Does this exterior sump pump sound like a good approach?