I was actually trying to find out when the Freight Rail blue colour scheme was introduced (planning to build a layout based on the SRA network in 1990 and not sure if including FR Blue liveried locos would be historically correct). In doing so I found this old thread, and reading some of the comments here I felt compelled enough to register and cast my vote.
I'd nominate the SRA Candy scheme in a heart beat. I can't understand some of the old-timers here rubbishing it and saying things like "How could you take a train seriously if it looked like that?" Remove the nostalgia glasses for a moment and imagine you're a tourist and a rail fan from overseas. What paint scheme on a train would look more interesting and distinctive to you? Drab brown locos/ carriages with a single yellow stripe? Or bold red, with yellow, orange and white stripes? The tuscan scheme was too earthy and drab, it blended into the background. It looks just the same as plenty of other old railways around the world.
The candy colour scheme was brilliant because it was unique- even overseas. The candy colour scheme is actually what gave me my first sense of state pride. Looking through railway books/ magazines in the late 80's/ early 90's I'd see the pale blue and white scheme of QR or the orange and grey VLine scheme- which made the trains look like giant stinkbugs, if you ask me! Only the National Rail green and gold scheme came close. But here in NSW, we had this awesome predominately red colour scheme that had not just one, but three secondary colours to it. I'd be proud to roll into an interstate terminal in a train that looked like that! I was proud that in my home state, THIS is what the trains looked like. If I'd grown up in Victoria or Qld or WA and seen that the people in NSW got to ride around in trains looking like that, I'd have been jealous!
On a purely aesthetic level, what I loved about the candy scheme (especially on the carriages) is that it evoked the romanticism of taking a long-distance train. Car trips as a passenger were cramped, bumpy and tiring. Air travel was cramped and boring. But the candy colour scheme made me think of the adventure that was part of long-distance/ overnight train travel. The red/ yellow/ orange/ white made me think of the sunset. Or the sunrise. It made me think of having dinner, going to sleep and waking up- all on the train. It made me think of travelling to far-away places I'd never been before. Like a family car trip but way more fun, smoother, less crowded and with room to stand up. It made me think of trips I was yet to take, places still to discover that were beyond my everyday life. I could get a normal train like I did in Sydney most weekends. Or I could catch a train that looked like THAT.
I've seen the sights in Paris, London, Rome, San Francisco and enjoyed Disneyland in the USA and France, I've ridden the Eurostar and the TGV, the XPT and taken a trip back to the golden age of steam behind the Puffing Billy and #3801. But I regret that I never got to travel long distance on a candy express with the sun setting on the horizon, knowing that I'd wake up on board an awesome looking train, in a city/ town I'd never been before...