Hmm, thanks for the thoughts guys. Yeah, my impression of the 16gb model is that it would be doable, but less than ideal. My hesitations with getting a 16gb 4s are mostly related to pics/vid/music. I like to keep a good bit of music on my phone as I listen to it daily (subway, working out). In reality, though, I don't actually need more than 3 or 4 albums or playlists at a time because I don't listen to ALL my music every day, it would just mean having to manually manage the on-phone music on a regular basis. Other thing is that I hear the camera on the 4s eats up a lot of space. Day to day use it would be fine because I could just dump stuff to my iMac, but what about vacations, etc where I want to take a lot of pics/vid but won't be able to sync to a computer for extended periods of time?
Not too worried about apps - I tend to keep them fairly low. My biggest app that I MUST keep is Garageband, which takes about a gig. Otherwise I'm pretty app-light.
I will probably try to find a good deal on a 32/64gb unit, but I'm just weighing my options as obviously the 16gb is both cheaper and more widely available (buying off Craigslist).