> I would gladly trade that for the additional mental steps of deciding which service to search and what the bang shortcut is for that service.

There are hardly any mental steps plural, if any mental step at all. Give it a try and see if there's a bang that doesn't make sense.

Examples:

!g - Google

!b - Bing

!gm - Google Maps (also !gmaps)

!bm - Bings Maps (also !bmaps or !bingmaps)

!d - Dictionary (also !dict and !dictionary)

!t - thesaurus (also !thesarus)

!gi - Google Images (also !gim)

!gh - GitHub (also !github)

!yt - YouTube (also !youtube)

!cpp - C++ reference from cplusplus.com

!hn - Hacker News Search

!aur - Arch Linux User Repo

!trulia - Trulia

!domain - domain name search

...etc