FS Navigator Replacement

I use FSbuild, but it's got an awkward interface and the map isn't anything to get excited about. It does a fine job of creating flight plans (and saving them in formats readable by FSX and most addons) once you figure everything out.

It's also got aircraft perfomance data built in, for fuel planning purposes. That comes in pretty handy when figuring out TOGW and such.

You might also try Flight Sim Commander, it is the closest thing to FSNav, and will give you SID's and STAR's and auto fly your AC for you. Though there will be a big learning curve. All SID's STAR's and airways are up datable via NAVIGRAPH.