Can I register a retail boxed copy of a game with Steam?
I personally do not like to purchase games digitally. There's just something magical about going to the store, picking up a boxed game, staring at the amazing box art, bringing the game home and putting the disc in the drive.
That being said, I know that several game distribution companies are leaning more toward digital distribution, with[Steam holding a large chunk of that market.
Is it possible to buy a retail boxed copy of a game, but still get the benefits of Steam (automatic updates, install on multiple computers, etc.) ?
It depends on what game it is. Obviously Valve's own games are possible to register on Steam. Call of Duty: Modern Warfare 2 also comes to mind since that one has to be played via Steam.
Here is a list of all retail games that can be activated on Steam: https://support.steampowered.com/kb_article.php?ref=7480-wusf-3601