Re: Which lines?
The floater as you say is a must have. With the other two lines, you have a fair bit of choice. Intermediate lines have some advantages over floating lines when casting in windy conditions and to very spooky fish (if you use a clear intermediate, you can shorten your leader which usually translates to better leader and fly turnover), but they really don't fish much deeper than a floating line would with a longer leader. To get down into that 2-5 feet depth range easily, I would suggest a type II sink tip. Below that, you can go to a type IV or V sink tip or full sinker. I fish with both full sinks and sink tips. Sink tips are easier to pick up and recast. Full sinks do get down faster, but they sink "belly down" which is means you have to retreive most of the line before recasting. Integrated or density compensated sinking lines "sink tip down" are a good choice. These integrated lines (which are really sink tips with an intermediate running line) do cast a country mile as well.