I keep all of my music, videos, podcasts, etc on my iPhone (16gig) for keeping with me wherever I go, and I also keep it all on my 30gig iPod in the car. I don't like using the touchscreen while driving; I much prefer the click wheel.
My iTunes library is about 51 GB atm so no. Then again, I've never had an isse with selectively choosing what I carry with me, be it iPods or iPhone. Music-wise, I have about 4 GB on my 32 3GS and it meets my needs.
I put "Yes, all of it" even though I only have 70% of my music on it. I don't keep 100% of music anywhere (I have CDs I haven't ripped onto iTunes, and I have MP3s on my computer not on my iPod).
I kind of see it as a waste to have an iPhone and have no music/media on it (after all, one of its top features are the iPod aspect).
But I can see people not wanting to waste battery life on media. Either way, you should at least put music on it and use the 16GB you paid for or whatever and maybe in that one random time you need a tune, there ya go.
i keep rotating play lists. currently have 71gb of music so until the 128gb iphones come out this is the only option. I use simplify media often in the case of wanting to hear something not on my phone
I keep about 5GB of music on my iPhone, but only as a back up for if my video iPod dies when I'm out.
I tend not to listen to the iPhone otherwise. I'm not one of those people who can only have a little music with me, I always end up wanting to listen to something random that hasn't been synced. I need a full size dedicated iPod
Haha well... I have around 60gb of music on my Mac in iTunes and several gigs of videos. (More on another computer)
Definitely not going to fit on my phone. Also, I don't need it all on my phone. I use most of the space for apps. I treat my phone like an iPod Shuffle or Nano.
I sync only a few playlists:
iPhone (One with songs I want to make sure always sync)
Top 25 Played (Smart Playlist)
Top Rated (Smart Playlist)
Songs with < 2 Playcount (Smart Playlist)
25 Random (Smart Playlist)