The Quick Version
If you have zero time to read all this stuff, get a Macbook Air. Its not the best option in all cases, but you're in a hurry and its good at most things and reasonably safe from viruses. The downside is cost (about $1,000). Invest some time reading these pages and you might get a machine that's even better for your particular needs and it might be as low $200.
Start with Windows or Not? to find out more.