In cases I've read about where someone was about to get busted and then did something stupid like smashed their hard drive against the ground, all they accomplished was digging a deeper hole for themselves as now they created more criminal charges against themselves. Besides now looking as guilty as possible.

Wiping is good but it also shouldn't look like the device was wiped unless it was stuff you don't really care about like financial documents etc. in which case it wouldn't matter. I know some software will wipe replacing those 1's and 0's with other files you specify, so you can "wipe" with Simpsons episodes for example and everything looks a lot more kosher. I've only read about that so can't recommend it, but would suggest anyone looking to wipe data securely look into it.

Also note that the process is completely different for HDDs and SSDs, for example. For HDDs there are 3-pass and 7-pass options that are considered secure (and take an incredibly long time - like days), for SSDs you "flash" the drive (that might be the wrong term) and it takes only a few seconds.