Lots of places -- coinbase, bitsimple, localbitcoins, the xchnage section of this forum.
Ok, let's start this again. And why would I do that? When all I need to do is press Paypal button. Or Visa Button.
OK, sorry that this has been blown past. It deserves an honest answer.
Before you could 'just press the PayPal button', you had to create an account with PayPal, right? Then link that account with another funding source such as a credit card or a bank account, right? Then earn money, and put that money in the linked account, right? Well, in a similar fashion, you don't just get awarded BTC as a birthright.
Before you can spend bitcoins, you need to have some. There are many ways to accomplish this. As you seem enamored of old-world money mechanisms, I will describe what I think is the closest analog.
Go to Coinbase.com. Create an account and wallet there. Link it with your bank account and or credit card. Use Coinbase's handy interface to purchase bitcoins from them using funding from your liked account. Boom. You know have easily spendable bitcoins. In something very close to the PayPal model of doing business.
Now to spend them, it is as simple as choosing bitcoin as the checkout means of payment from a retailer that accepts bitcoins. Examples would be NewEgg, Expedia, Overstock...
You can also make your Home Depot purchase (many other retailers as well) quite painlessly, through the intermediary of Gyft. But you probably want to get some experience with the basics first, before adding this next layer.
We are not born knowing how to use bitcoin. Neither are we born knowing how to use wire transfers, credit cards, checks, or even cash. You've been around these other financial instruments your entire adult life, so you no longer think about the learning process in regards to them. But you should not expect using any new financial instrument to come with zero learning required.
Yes, things require a little effort. Less now than a year ago. In another year, they will be easier yet. Either go through the pain of learning now, or wait another year for the next simplification. There will still be learning required, but likely much less. All you'd be giving up is the possibility of another 10x possible increase in the value of the bitcoins you hold.
But stop whining - we're not going to do it for you. We have our own lives to run.