RO/DI Filters - What do you have/like/dislike?

So I understand the importance of using RO/DI water, but I'm wondering what kind of filter everyone uses.  I just set up my tank and so far, I've been using RO/DI water from the Culligan water station at my local Wal-Mart.  It has to be better than what i get out of the tap and it's not expensive.   I feel that I can get away with that for now since I have such a small tank and can purchase an adequate reserve to keep at home.
I've seen a wide variety of different filters and read different things about all of them.  Also, I've read that certain things are more important for some areas than others (i.e. due to chemicals used to treat CR water, I've read that some recommend a dual carbon stage, etc)....what does everyone thing about the best type of filter to use for the Cedar Rapids water?
I'm interested in hearing all of the details including brand preference, reasons for your brand preference, do I need a pressure pump or not, daily production capacity guidelines, maintenance costs, usage recommendations, etc.
Thanks for all your help.  I really value to the input from all of you.
--Aaron