It's a fine line to reach just the right balance when plus sizing wheels and tires. Yes, it's more personal taste, but too small or too busy and you miss by a long shot, too big and too awkward looking and you miss... it has to have a good balance of wheel and tire, and it has to compliment the cars features and character.
But they can make the largest impact on how the car looks (other than paint) the biggest bang for the buck appearance wise...
I had brand new Craiger SS wheels on my 68 back in the 80s' Jim, there was nothing like fresh chrome I tell ya... I don't think I would go that route today with so many choices out there now... but than again I don;t think I could decide on one set anyway