JPG is ok, BUT if you intend to edit anything then after time you save a JPG its compressed again and as its a lossy format you WILL lose detail EVERYTIME you save it
With RAW its literally what the sensor has recorded which is why the filesizes are so huge, so if you overexpose or get it slightly 'wrong' then its easier to correct without losing any quality when you save it, where JPG you WILL lose detail when its saved after editing as the camera has already processed it before saving it
Personally I use RAW, but have to use JPG (set about 85%, where a lot assume 75% as a default compression) when sending images to friends via email or uploading to FaceBook or flicker as they don't like big filesizes, but keep the original RAW files for backup
I also use IrfanView to batch convert the Nikon NEF RAW format to JPG as its 100% free and for simple but good batch conversion with some basic filtering its quicker than loading up PhotoShop or LightRoom
A decent class 10 16GB memory card is very cheap compared to what they were 12-18 months ago, so even shooting with RAW I can get a good few shots when on continuous shooting mode before the camera saves it all
I carry 3-4 memory cards so running out of space isn't really an issue, and all are class 10 that has a MINIMUM transfer speed of 10MB/sec
In UK you can pick up 16GB class 10 SD cards for less than £10, so cost or storage isn't as expensive as it used to be