So what does this mean? Well, I'm switching sides for a moment to give you bad guys out there some ideas to mess with any examiner that may end up digging through your cess-pit of a computer. Yeah, they'll probably still find the dirt that's there, but the least you can do is make it interesting for the poor guy/gal who has to turn over your digital midden heap in the course of their work. So, without further ado:
Investigation Slowing Strategies
Funny Videos - This is probably the very best way to slow down any investigation. Have lots and lots of funny videos stored throughout your drive (Tip: this is especially useful if your nefarious misdeeds are video based). Now, don't get lazy and just download the most popular funny vids - we've seen them all. Get creative. Really look for those out-there, maybe a bit geeky gems that will keep any investigator enthralled, despite the clips' complete lack of relevance to the case. Extra marks if you create your own.
File and Folder Names - Investigators are well aware that there usually isn't a folder entitled "All My Illegal/Unethical Stuff" on a drive that will hand them the investigation on a platter. But why not throw out a red herring? Create folders with sinister names that contain pictures of bunny rabbits and clips of Dane Cook comedy routines. Something along the line of Tobias' business cards (from Arrested Development) is a perfect example.
Internet Search Terms - One of my favorite things in any investigation is to see the progression of search terms people use on their computers. The sequence leading up to generating that perfect term to get the search engine to spit out whatever website they so desperately want to find can be an incredible insight into how the human mind works. Bearing that in mind, try to create as many assinine and unintelligible search terms and then run them. Hey, maybe you'll end up being surprised by what you find.
EDIT: After seeing some well thought-out responses to this post, I have to come clean. The intent was pretty much a tongue-in-cheek reference to my own foibles doing exams (i.e. having way too much fun with some of the funny videos... btw, have you seen this one? Brilliant!...), and a bit of forensic humor inspired by comments found in happyasamonkeys blog. This is my Screwtape Letters. I actually feel a bit humbled by the responses. Maybe I need to go legit and leave all this satire behind!