My problem is that I'm impatient: 5 seconds is too too for me to wait for a machine plugged into a wall outlet to become responsive, and all of my computers to date have been desktop machines. But I agree with you that standby is very important on a laptop.
I have never owned a laptop myself, but I likely will end up buying one at some point and have been considering what I will be doing as far as power management goes. I'm considering running the system 24/7 without the battery (to conserve it) and plugged into my desktop keyboard and monitor when it will be at home for a week or more at a time during which point I may turn off all power management features, and shut it down and plug the battery in when I leave, using various power saving modes when necessary... but I will still most likely just shut down whenever possible to get the biggest savings.
Overkill? More work than is typically done? Well, what can I say... I'm really, really not a fan of power management features, but I will use them when absolutely necessary, and even then only under special conditions. :p
If I'm going to have to wait anyway, the way I see it I might as well just go all the way and shut the machine down completely, saving the most battery when not in use for an extended period of time.