How much editing do you do on each photo?
You get iPhoto bundled with OSX and it will handle RAW files as well as JPEGS. The editing functionality is a bit limited though but will let you straighten, crop, adjust colour and exposure etc...
Next step up from there is Aperture. Costs a bit more, but is a lot more powerful.
There's also Adobe LightRoom, which is similar in price and functionality to Aperture.
If you're into full on editing, there's Photoshop, but that's expensive.
Aperture and LR both have trial versions available for download. Give them both a go and see which you prefer.
There are others to consider as well, like Googles Picassa for example.