Page 14 of Haynes Automotive Repair Manual 1979 Thru 1985 under the Essential DOs and DONT's section it states:
DON'T start the engine without first making sure the transmission is in Neutral (or park where applicable) and the parking brake is set.
What the hell I always start off up the car in 1st . Is this supposed to be better because I don't really notice a difference.

 

If the clutch is in, it doesn't really matter. They just say that because if the clutch is out and the car is in gear, the starter will try to push the car forward (bad for starter, may hit something, etc.). Newer cars have inhibitors that don't allow the starter to engage unless the car is in neutral and/or the clutch is in. I usually start the car in neutral, myself.

 

Its do you don't accidently take your foot off the clutch and jump the car forward. It is more driver safety orriented.

-Marques

 

Oh alright that is what I was kind've thinking because I didn't really think it made a difference. Thanks for the clarification.