I agree with some here who bought the 32 more for a peace of mind, but don't consider myself the type that needs to carry my entire library of music and video. There is a $250 iPod classic at 160GB that I can buy to store all that.
I just stream. No need to carry too much music or video everywhere I go just to "fill memory"...
Some my most important content really are my personal photos and home videos. Those are my lifetime worth of great memories. I can store my music, videos, and apps at 7GB with my iP4, and use the other for mainly photos and home videos. My problem is I used to do VGA (640x480) settings for my videos because my P&S camera maxes out to that. With 720p, it is going to be a pain. HD recording is both a batt and memory hog. A 30 sec HD video can consume as much as an entire music album at over an hour. Uploading to my YouTube account is now a must. And I did use VGA for still pictures when I went to Asia three years ago which was my favorite photo album. Not going to look all that great now on a 960x640 screen. So if my photos is also taking too much at taking space, I can always upload my 2,000+ pix at Photobucket and I get easy access with the app.
Storing it online and streaming is now the key. There is never enough GB to go around with higher settings than the ones we have. Good thing I am not about excess. Coming from a 2GB with the Nokia N82 and a pair of 8GB first gen iPhone/iPod touch, 32 is my "Magic" number... (for now)