Some recent mods, not really worth taking pictures of:

--pitlock locking skewer on front wheel, to simplify and speed up my locking routine (and have fewer locks to carry)
--swapped stock 11-28T cassette for a more generous 11-32T, to give me a lower hill-climbing gear (I have a very nasty hill on my commute home)

The Dahon Traveller Rear Rack is working great. When I need to carry it, I bungee my NYC Kryptonite u-lock on the lower rails, leaving the top of the rack clear for attaching other items. A single bungee cord works great for attaching a small bag to the top. Last week, I got a Wald 582 folding rear basket that I bungeed to the rack top. I like the fact that I can remove it quickly and collapse it down for storage. I haven't tested it on the road yet, but I saw a woman by the Union Square Trader Joe's today with a milk crate bungeed to the rear rack of her folding bike (in the same way I attached the Wald), and she said it's the perfect grocery getter and she has never had a problem with it slipping when loaded.

I am trying to streamline my bike commuting routines to minimize futz time (folding, loading, locking, etc.).