If you only want one firearm and do not want to start with a .22 I would recommend starting with a .38 Special revolver. Smith & Wesson or Ruger would be my first choices. They are simple but effective. You may later want to try a semiautomatic but the revolver is a good place to start.
I go with the Ruger for a nOOb. Costs less, highly effective and reliable.
Go for nicer or fancier tools after you have some time in on your first.
Well...tell pepsi_junkie that, not me...I already have a few handguns... :)