Heading to Osaka, Kyoto and Hiroshima

Heading to these places next year only - starting in Hiroshima, then moving onto Kyoto and Osaka.

Is it worth me getting a rail pass, or will it be more cost effective to buy tickets on the day of travel?

Cheers!

Regular tickets will be cheapest. And a highway bus between Hiroshima and Osaka will be considerable cheaper than the shinkansen:
http://www.japan-guide.com/e/e3404.html?aFROM=2157_2160

If you travel in March 2015 or later, the new Kansai Hiroshima Area Pass may be of interest depending on your exact movements. If you just travel Hiroshima-Osaka-Kyoto, regular tickets will be cheaper, but if you backtrack a little or do side trips, it may pay off. That pass, too, is considerably more expensive than highway bus travel, though.

Thanks Uji, much appreciated :)

Are you going to teleport from Australia to Hiroshima? ;)

Flying to Seoul, then to Hiroshima!