To force chrome to reaload css and js:
Windows option 1: CTRL + SHIFT + R
Windows option 2: SHIFT + F5
OS X: ⌘ + SHIFT + R
Updated as stated by @PaulSlocum in the comments (and many confirmed)
Original answer:
Chrome changed behavior. Ctrl + R will do it.
On OS X: ⌘ + R
If you have problems reloading css/js files, open the inspector
(CTRL + SHIFT + C) before
doing the reload.