Well, this is going to be my dilemma when the next generation iPad (hopefully with retina display) arrives.
Currently, I own a 32 GB + 3G first generation iPad. When the iPad 3 arrives, I don't want to spend another $699 again, but at most $599.
I just need that 32 GB because I'm afraid I will not have enough space when I go for the 16 GB, but if you keep things organized (delete things you don't use anymore), than 16 GB is sufficient.
I have found that 3G connectivity is extremely useful, especially when going on holiday. I just put in a SIM card and I can immediately browse the web on the nice 9.7" display. If I own a wifi-only version, that's not possible. I can't create a wifi signal from a 3G signal for my iPad so that's a problem. I also found that the extra GPS chip is extremely useful: last year around Christmas we were in Germany and the roads are terrible over there (when it's snowing and freezing). Certain areas were flooded as well and it was just very unclear where to go. The iPad helped out because I opened up Google Maps and everybody could clearly look at the map because of the bright IPS display. GPS obviously helped a lot.
So, that's why I am in a dilemma. At this point, I wouldn't know what I would do. A 16 GB + 3G (4G?) + GPS iPad 3, or a 32 GB WiFi only iPad 3.
I hope Apple decides to bump up the storage:
$399 - iPad 2 16 GB (budget model)
$499 - iPad 3 32 GB
$599 - iPad 3 64 GB, iPad 3 32 GB + GPS + 3G (4G?)
$699 - iPad 3 128 GB, iPad 3 64 GB + GPS + 3G (4G?)
$799 - iPad 3 128 GB + GPS + 3G (4G?)
In that case, I would definitely go for a 32 GB + 3G model. If they keep the same pricing as they have right now, it will be either the 32 GB wifi only model or the 16 GB + 3G model.