Nutrition/Exercise Tracking on iPhone?

Hi Ladies--

Today is my birthday and my husband gave me an iPhone.

I know several of you use programs on your Blackberry or iPhone for tracking your nutritional intake (and possibly exercise too). Are there specific applications you recommend? I went to download an application for such a purpose, but there were so many to chose from I didn't know which one would be a good choice.

Any input greatly appreciated.

--Paula