The idea behind some of these countermeasures are so if someone steals your laptop, they can't access the data. The article comes from the 'beyond paranoid' side, since cold boot attacks especially are require a lot of setup (of course, once you have a laptop, take it to a lab). The firewire attack is as easy as plugging in a cable though, but still requires someone with the no-how to find the password.
For most people, just having an encrypted drive is enough, since their data probably isn't valuable enough for people to go out of their way to steal it. You are mostly trying to protect your data from ordinary thieves.
The whole point of the "Evil Maid", "Cold Boot" and "Firewire" attacks that are described in the blog post, is that physical access to the machine is required in order to pull them off...
For most people, just having an encrypted drive is enough, since their data probably isn't valuable enough for people to go out of their way to steal it. You are mostly trying to protect your data from ordinary thieves.