I have a word document I'm constantly updating. The first page is all the tricks I'm currently performing. They're broken up into the categories: Cards, Other, and Set-Up/Situational. This list is my current performing repertoire. Anything in italics on the list means it requires a gimmick, otherwise it's impromptu.
On the second page of the document is a list titled "Reserve." On this list I put effects down I've performed in the past but haven't been using lately, don't use often enough to consider them part of my regular repertoire, or effects I'm just playing with but have yet to decide if they're going to be something I want to keep.
The pages below those two have a couple scripts or notes on some of the effects, alphabetized.
I think it's really important to keep your effects organized. It helps you look at your magic as a whole and can really help you in deciding where you want to go, where your repertoire is weak, and how your magic might be perceived by others. It also helps give you a "big picture" on your magic--do you notice you need more opening effects? Impromptu material? Too many transpositions? Etc.. I bugged a magic friend of mine to make a list for over a year and he never did it. One day he called me up and said he'd done it and told me how much it helped him focus his repertoire and how he wished he'd done it a long time ago. So if you haven't done it yet, DO IT!
Also, it's really help me cut down on what effects I want to perform and really focus on a select list. Over the past two years I've noticed my list has gotten smaller and smaller, and I'm really proud of that. I remember reading or listening to an interview with Eugene Burger saying he used to perform 40 effects and he now had it down to 29. He said, "If I can get it down to 20 effects I think I can be a real star." Great advice.