That's a tough one to answer without knowing your needs. I went for the Internet everywhere model, because of my needs. To me this magnificent device is more an Internet portal than a permanent storage of my pictures etc.
Wen I travel I usually pack it with a couple of episodes of some of the tv series I'm behind in and the daily newspaper and such. Besides that some obvious apps and games. For that my 16 is more than enough.
My iPad 4 on the other hand is used as a small computer on vacations and at home. I went for the 32 with that to be able to empty my dSLR camera on it and be able to browse the pictures we take while abroad.
So depends on your needs.
Well, the main uses will be music apps (GarageBand, Moog, Korg, NI...) and Touch OSC. except that i will use it when im on the road\flights (movies, games, music,books...) and in the house for internet, skype, itunes remote, and so...
Not sure how much i will use\need it with me in my daily life, coz till now i didnt fill the need to have iphone or smarthpone in general, still happy with my dual sim cheap Nokia
With my Galaxy tab, i used it till now only for flights (sometimes i preferred my old ipod touch instead for short flights) and in the house... but thats coz its useless, big and heavy to carry around even that it came with 3G (never bother to get sim for it)...
Now with the ipad mini its different story, since its smaller and lighter (and will have more use in general), i wont be surprised if i will start carrying it with me in my bag wherever i go... and if that will happen, it will be nice to have excess to internet everywhere as well, since i dont have iphone...
The ideal will be getting ipad mini with 32GB+4G, but that cost to much...