The MAC is good for word processing and Graphic Design, but loses based on expensive hardware. Apple doesn't allow 3rd parties to build hardware for them. MACs may be a lower target for virus attacks, but they are still on the list, so avoiding virus protection on a MAC will burn you in the long run.
PCs, yeah, a target for Viruses, but there's free scanners out there, and you can "Privacy Browse" on Google Chrome and Firefox browsers. Games! Games are made and tested on PCs. If there's a console game, than there's a PC version since they were designed, and initially tested on a PC before testing on the console. There are many PC makers out there, so price competition is fierce.
The size of the Laptop. 12.1 is currently placed for tablet PCs. I too haven't seen many laptops that are 12", but that size will be the breaking ground where Netbooks and laptops meet. If you were to find a 12" laptop, it would be a slim one with a bigger price tag.
Look for a 13" one where the price is just right with size, weight, battery life, and hardware. ASUS, HP, Toshiba, and ACER are good brands to start with.