Whilst apps are getting larger, it's nowhere near as bad as some are making out.
Ignoring a few huge ones, we're still talking a few hundreds of MB for even the bigger apps so it's not like you're going to install ten of them and run out of space on the 16GB model.
If you're not planning on loading it up with media then you'll probably be more than fine with 16GB. Of course, the counter-argument is that it's only another £80 for the 32GB, so if you're spending £400 already, what's another £80 to double the space? 20% more cost for 100% more space.
Ignoring a few huge ones, we're still talking a few hundreds of MB for even the bigger apps so it's not like you're going to install ten of them and run out of space on the 16GB model.
If you're not planning on loading it up with media then you'll probably be more than fine with 16GB. Of course, the counter-argument is that it's only another £80 for the 32GB, so if you're spending £400 already, what's another £80 to double the space? 20% more cost for 100% more space.