Have two different steams account for different games?
 

I am relatively new to the Steam gaming thing...
so I am wondering is it better to make my steam games on different steam account?
Reasons i want to do that is, this way my friends & family can play one game on the steam account while another can play another game.
If I put all the games in 1 account that would means when 1 person is playing a game, no one else can play / access the other games.

Do people usually do that? Any downside or problem if I do this?

no downside, you can sell the account later on too.
I personally like to have all my games in one account.

pretty much I have one personal account and then ... one shared account for L4D. When my friends bought the 4 pack, steam screwed up so they tossed in an extra copy. I suggested we make a new account for it, if any other friends wanted to play.

If that wasn't the case, I don't there would be an additional account tho.