First, welcome to the forum -
Second, this oft asked question seems to be a 'knee-jerk' of newbies here - now, there are thousands of apps available for the iPad; a search of the forum might help to get your started; also visit the Apple App Store which has their offerings categorized w/ plenty of comments & reviews.
But, I would suggest defining your specific needs! Why did you purchase the iPad, e.g. pleasure, business, or both? What will be your main reason(s) for using the device, e.g. entertainment (what type?), reading, other?
Answering these questions first will likely get you more specific responses; otherwise, you will receive a BUNCH of posts simply listing the favorite apps of the posters.