I think the key here is "being exposed to it so that eventually it becomes part of how I function?". If you never cull your online bookmarks or go through the things you've saved to ReadtItLater, you're in the same boat as you are with your file cabinet. Conversely, given the habit of reviewing/purging on a regular basis, you'll be exposed to it whether it's in a paper or electronic filing system.
Personally, I use SpringPad. As I go through my day, I add interesting links & bits of information...advice, things I want to buy, movies I need to see, etc...into springpad. At the end of the day or the beginning of the next (whenever I go through and revise my to-do list, I review the batch of "recently added" (I think they default into an "uncategorized" bucket) add the relevant tags, and quite often, eliminate a few--like the link for a new messenger bag that I wanted, but realized I don't NEED.
More importantly, as I'm going through and reviewing my tags, I am exposing myself to previously stored content, reminding myself of what's there, and if there's something that I need to get to or want to review, I can just add a tag for "immediate action" or something, just to remind myself to look at it.
That's worked pretty well for me...but only if I DO it. While reliability and access are important factors in any data/knowledge management system, be it paper or electronic, it's only worthwhile if you USE it. Find a system that's easy and intuitive for you to use. Then develop the discipline to USE it. Take a different paper folder on the train with you every day to work, and eventually you'll be cycling through purges and reviews. Read a link aggregator on lunch every day and tag things for future review or deletion. Once the habit develops, you'll find yourself managing your information a LOT better.