Think of yourself as the hiring manager/interviewer- What type of CV do you want in front of you? Its an easy answer- visually easy on the eye, keywords pop out, easy to read & clear format & structure. 

Hope now you can choose the right font and formatting. Be creative and dont be shy to experiment a little.

Hi Carmen,
I would tend to think that 10 is a bit too small and usually settle for 11 or 10.5. But more than the font, how visually pleasing it is is even more important. It should not be crowded, the most important information should stand out, one shouldn't have to think to know where to look for the relevant information... Print your resume and look at it.

Also don't hesitate to give it to people. Give them less than a minute and ask them what did they think of your CV and which information do they remember? This way you'll know if you properly highlighted the relevant information and if your CV was easy to understand.

Best of Luck for your applications

Usually they ask for a 10.5 font for a resume. But recently a designer friend of mine applied for a job at a company and the font size was not important to them. They don't have any resume requirements for a designer. He had a pretty creative resume that he got ideas for from Master Bundles, mostly he used fonts. And I thought his resume was extraordinary. But the employer really liked it.