16GB is way more than enough for me.
I don't believe in downloading lots of apps and games. I stick to the ones I need.
When it comes to music, I love TuneIn radio. As I listen to electronic music, it's got like thousands of radio stations. Though I do have around 2gb of music. But again, I only load what I listen and once am done, I sync new collection.
I don't like watching movies or any video file on iPad besides youtube. I'm a movie freak and I love watching in my home theather (It's not a theater, but I have made it like one

)
Reading news/magazines and books sometimes, I use news apps. I got like loads of news apps. I use Zinio app for magazines (it's an outstanding app if nobody has heard about it) and Kindle for books.
Most important use of iPad is office. I need that everyday. There are lots of files where I have to keep updating everyday and to make things flawless of using the file anywhere, there is dropbox. So all in all, it's a good thing for me.
And then ofcourse there is web browsing and stuff. Overall I like the way iPad shapes my life. It makes things very smooth and easy as I don't have to shut down or anything like MAC OSX. I do have Macbook pro but honestly, I use like once in a week.
So after all this i still got like 8GB! and one more thing. I got iPad WIFI 16GB. Now I can surf 3G internet cause I got 3G network on my Sony Ericsson Xperia X10 and I use Wifi Tether. Two reasons why not 16GB WIFI+3G, 1] battery consumption and 2] buying 2 3G connections - one for iPad and the other for my cell phone.
I don't need space cause in today's world you can store it anywhere on the internet and now we got wireless flash drives. I need fast internet. I'm waiting for 4G in India
