I have been involved in a number of exterior door projects but am no specialist and have not chosen most of the hardware, so take my comments with a grain of salt. With any luck Joe Calhoon will chime in here and his advice is based on a wealth of experience.
For a traditional look, there is a wide range of hardware available and a wide range of cost. Deltana has a decent line of ball bearing hinges at a fair price.The simplest, strongest latching/locking system is a passage set (locking turnbutton or not) plus a separate deadbolt. Omnia is one maker that I have seen quite a bit. More elaborate is a mortise lock with integrated latching/deadbolt. Baldwin is one brand I have used. The internals and finish hardware are often from different manufacturers, just be sure they are compatible. You will need bolts to secure the fixed leaf whether surface mounted or concealed in the meeting edge.
For all types, especially mortise locks, ordering the correct orientation is critical so it is helpful to have a person at your vendor that can guide you. Be sure to review specs carefully before confirming your order.
Multi point hardware is a good choice, especially if the fixed leaf is used often. It will ensure that the leaves stay in plane. Hoppe is the brand I am most familiar with. I believe there is less design variety available in the manufacturers' finish hardware, but there may be more options from third parties. Again, careful specing is important. For a contemporary design the concealed hinges made by Tectus can't be beat. They allow for easy 3d adjustment after the door is hung. $$$.
Proper air sealing is critical. As Richard Coers pointed out you will need an astragal with a seal and quality seals all around the perimeter. I like the silicone rubber flipper seals from Resource Conservation Technology. There is inevitably a small gap at the bottom corners where the sweep and edge seals run by one another. This is usually filled with self-adhesive felt "fuzzies".
Automatic sweeps are a good idea- I have used Pemco and they work. They do require a sizeable dado in the door bottom (around 7/8" x 1 1/4") so unless you have a huge shaper it is wise to precut the grooves in the stiles and bottom rail prior to assembly and expect to do some fine tuning afterward. If you use multi-point latches the layout of the sweep groove relative to the latch strike groove must be considered.
I have always used wood sills (white oak is a good choice), but there is a wide variety of metal ones available. Make sure there is a thermal break under the door. Be aware of codes (ADA requirements).
Be aware also that any glass in or near a door must be tempered or laminated.
Best of luck with your project.