If you have time:
Order a nice set of hubs: I suggest getting the Arvon hubs, advertised on the buysell, for riding around the city they are light and will last forever.
Rims: If you like the DT swiss ones, go for it. Otherwise I am really a fan of openpros.
Stem: you dont need some fancy track specific stem for on the streets, find a cheap stem, upgrade later
Handlebars: your choice
Seatpost: Miche supertype seatpost is cool and affordable, but you can probably find a nice vintage aero seatpost (Old campy ones are nice, I sold one for 50 bucks so I know they can be found afforably and cleaned up)
Seat: If you like the brooks, do it. for me, I like somthing lower profile.