On launching developer tool in chrome cursor changes to round black

In Chrome Developer Tools, in the lower right corner click on the gear icon. That will open dev tools settings screen. Uncheck Emulate touch events parameter there and you'll get your normal cursor back.

Update: It seems like newer version of Chrome(at least my 33 beta) hid that option even deeper. From the developer tools show the console by pressing Esc then switch to Emulation tab and then Sensors sub-menu. From there make sure Emulate touch events is unchecked.