Mine's a T3, so pre-dates the current models, and I didn't have a choice of getting a two-speed at the time, it was three speed or six speed. I decided that having the dérailleur with the hub was unnecessary, especially since to use the entire range in turn, you have to alternate between changing the hub, and changing both! If I bought one now, I may go with something like Charlotte suggested, just using the one ratio for pulling away, and when pulling stupidly heavy loads on the trailer.
I used to use my Ex's Brompton which didn't have an extended seatpost, and it was OK for short distances (a mile or two), but when I bought my own I thought it would be a good idea to get that additional distance, and it's a lot more comfortable. I'm 6'3" with about a 32" inside leg.
I've got the rear carrier and hardly ever use it, the front luggage block is more useful, I could do without the carrier, but not the luggage block! Likewise, it's dead easy to fit some LED lights for emergencies, rather than rely on the dynamo. Mine died after six months, and rather than faff about with findind the dis in the wiring, I just binned it and went over to battery lights permanently.