Very tough choice! I like the red colour for you, but I love the gold polka dot dress too!
Ok, clearly - I'm no help. It would be handy if the red dress came in polka-dot, but I guess not, eh?
Meanwhile, red is one of my favourite colours, so this might be influencing my opinion in a way that isn't quite fair.
You know what? In the end, I think I'd go for the polka dot in the gold colour, just because it's different. I'm sure you have lots of red pieces, but you probably don't have a polka-dot gold dress? I'm already imagining the gold polka dot dress with a cropped,fabulously faded denim jacket, some cream coloured accessories and the like. Maybe a 'pop of colour' in the form of a red clutch?
Maybe the red (although fabulous) is just too predictable?
Ok - enough said - I vote polka dots