I personally don't use a screen for the DFRPG, but I've always appreciated them for other games that involved charts.
For my current DFRPG, I just have a single folder with attached notebook and the two-page cheatsheet from the back of the book for myself. That tends to cover what I need.
As for other games, if a GM screen didn't exist, or didn't match what I wanted, I would go ahead and make my own, each having a cost directly proportional to what I wanted to do.
For an old World of Darkness game I ran for a college club, I printed out typed up versions of the charts and glued them to a piece of poster board that I had folded to act like a GM screen. I then glued a variety of artwork to the other side to add some color and theme.
For that game in particular, I needed two tri-folded sheets, which basically summed up to one board cut in half, folded, and a bunch of charts glued on. Not including printing, this project set me back by a night and about $8 (needed scissors, tape, and glue as I had none of the above), but was only really viable for that particular game system and how I was running it.
A better option was a reusable screen I found from the forums. I took two three-ring binders, some clips, and transparent folder inserts. I clipped the two "screens" together by the ends, loaded the inserts with whatever information was relevant to the game (similar tactic to the above: printouts of the needed charts, story arc notes, etc), and filled the outer-sections with images relating to the game. This set-up cost a bit more, but proved to be useful for the three different game systems I ran with it.
I'd suggest looking at either of these options and just loading it up with whatever in-game notes or house rules you need, your player's Aspects and powers, and whatever shortcuts you need. Otherwise, just put them on paper (or index cards) and go from there.
Hopefully that was at least somewhat useful.
--Crion
