The massive departures hall:
There will be two ways to reach T5: by road and by AirTrain. By car, you'll be dropped off on the upper departures level, like most airports you're used to. By AirTrain, you'll follow a swooping elevated walkway over airport traffic to enter T5 at the northern end. Either way, you'll end up in the departures hall pictured above.
Once you're in, you'll head straight for security, which has been pushed to the very forefront of the terminal. Plans call for 20 lanes in one big checkpoint; the current JB terminal has about half that many, split into two checkpoints. Since you've already checked in from home, this is the only line you'll have to stand in--and you can tell how long you'll be waiting the instant you walk into the building. Genius.
The massive marketplace:
After passing through security, you'll enter what JetBlue calls "The Marketplace," a central 55,000-square-foot food-and-retail space. Details are still secret, but expect to see big flat panel info screens, advertising, more dining options than JB has in the current terminal and free WiFi. This is where you'll be hanging out if you get to the airport early.
Speaking of, since you've skipped check-in lines and front-of-the-airport hassles, you might actually get some work done at T5. Good sight lines help you keep an eye on things from the marketplace, and with info screens everywhere, you won't be tethered to your gate.
If you still feel the need to keep an eye on your plane, plans call for copious seating, with 100 seats at every gate. Since JetBlue's A320s seat 150, that'll give two-thirds of the passengers on a completely full flight a place to rest their feet.
The massive baggage claim:
What does T5 promise arriving passengers? The bathrooms are accented with stainless steel, and the entrances poke out into the terminal's hallways, allowing you to spot them from a distance. No more frantic searching for that tiny restroom sign after getting off your flight!
Baggage also should be easier to snag, as the new building has six massive luggage carousels. After you've grabbed your stuff, it's a short walk out to the curb for a cab or bus, or you can hike back upstairs to the AirTrain.