Consider Pulse SMS (requires a subscription, which I've gladly paid for desktop texting), which has a desktop app and allows texting from the desktop. Not only that, they backup your SMS messages for you so you'll never lose a message as long as you're using Pulse.
If you want to use the built-in Messages but also want to text from the desktop, consider Push Bullet, which provides an interface to ALL the notifications, contacts, SMS, and more on your phone, but allows you to text from your desktop through your phone.