Adj. Superb, perfect. “For the lemony, pan-seared garlic chicken with baby spinach and a mashed potato gratin ($21), he suggests the ’97 Edmeades zinfandel, which is a spot-on pairing.” (Los Angeles Magazine, May 2000)/”The vision President Obama laid out in his State of the Union — future forward and focused on winning the clean energy race through innovation, freeing business to compete and investing in research and education — was spot on.” (Huffington Post, January 27, 2011) Google Ngram.
notoneoffbritishisms.com 
Hi,
I’m BrE and use the expression ‘spot on’ sometimes, but I don’t quite agree with your definition of ‘superb, perfect’. For me it’s more like ‘absolutely right’, which I think your examples actually demonstrate. So the wine is just right for that dish, and according to HuffPo, Obama got it absolutely right. It’s not about absolute quality, but about suitability or correctness.
I’ve just checked in Oxford Advanced Learner’s Dictionary and they have it as ‘exactly right’. (I’m allowed to say ‘they’, I’m British!)
I find the existence of your blog quite amusing, given that in Britain some people are totally convinced we are being swamped by Americanisms.
Heard “spot on” this morning in a commercial for a local hospital’s system of pinpointing the prostate for radiation treatment through use of GPS.
The Philadelphia Inquirer’s pages have contained at least one “spot-on” every day for the last week. Sadly, there’s not much else about the struggling Inky that is worth much as it has devolved into a collection of articles from wire services written by syndicated staff and right wing nuts of the Krauthammer stripe. Is this “spot-on” thing a marker?
“Spot on” is heard toward the end of this video: http://www.aol.com/video/high-schooler-lands-milliondollar-book-deal/517737130/
6 years into the future… “Spot on” is now completely normal here in the States. So this was definitely a good call!
I remember thinking some years back several people saying it but it seemed to coincide with their love for Dr Who and other British Programming which at that time was still somewhat niche.
Then, last Summer I was watching an episode of HBO’s the Wire where an undercover cop had to pretend to be a Brit. One character suggested he say “Spot on” to sound more authentic and no one, including the cop, knew what that meant. The person had to explain it to him.
This just confirms to me that Spot On was still very much a solidly British saying not (relatively too long ago) because if memory serves this was in the second season of the series which would place this episode somewhere around 2003.