All - I was having some issues with blocks not loading or loading and vanishing while moving around the game. Placing and picking up water seemed to be the catalyst for most of the issues. http://tinypic.com/r/2evztol/8 I found that having Chunk Loading set to 'Multi-Core' was the problem. After changing the setting to 'Smooth', all issues were resolved. If you are having this issue, please change Chunk Loading to 'Smooth' before reporting it.
I tested it on 1.8 and 1.7.10 (both without mods using MC launcher) and there were no issues. I was only having issues when I was running my 1.7.10 mods. Once I changed the setting, it allowed me to run the mods, just like pre-1.8 update, without issues. Options -> Video Settings -> Chunk Loading (right column about half way down) - V