Girl bicyclist here. With the seats, the ones with big fat asses will look tempting-- don’t do it. Somehow big huge fat cushy ones rub against your legs too much and cut off your circulation and all is very bad. You will get used to your seat in a couple of weeks–trust me (I also refuse to get into the recumbent issue. I am personally more used to the upright, and anything but a very long-base recumbent feels too twitchy for me and makes me nervous, comfortable as they may be. Keep them in mind when you start thinking about an upgrade-- there is a reason that these zealots are out there). Padded shorts will help-- maybe just get the ones with the chamois pad, since the ones with liquid gel and such sort of explode in the dryer when you forget that they went into the laundry.
I have a seat by a company called Terry which is glorious-- the middle of the front part is cut away completely so your sensitive bits don’t really get sat on-- weight stays on your ass bones where it belongs. They look sort of creepy, but man, they work well. I think various companies use these now. Also good for guys worried about their weenies.
While I’ve been biking for years I still prefer toeclips and street shoes for normal tooling around-- I’ll put on cleats and clipless for huge epic rides (30 miles+). I also have a pair of bike shoes that I haven’t put cleats in-- they have very solid soles so they don’t bend when you pedal (more power transfer) but I don’t feel like a goon wearing them around campus (normal colors).
Yes, you want a brain-bucket. They suck much much less than they used to-- they are light and fit correctly and comfortably, and you’ve invested too much in your brain to wind up with it all over the road.
Padded gloves are a good idea, too. Oh, one thing no one’s mentioned that I noticed is lights. Get a red blinky one for the back and a white light for the front and leave at least the back one an all the time-- when it gets later in the year and it gets dark earlier. . . You know. The front light might not help you see much, especially on the road where there are street lights anyway, but the important point is that CARS see YOU.