I still occasionally hunt with my dad's Valmet 16ga O/U. He got it as his 60th birhday present in mid 60's, complete with a brass plaque embedded in the stock, and that gun really deserves to be taken out to the field every now and then.
Other than that, 16ga seems nearly obsolete these days. Finding ammo is a real PITA, anything second hand chambered to 16ga gathers dust on gun shops' shelves and it's been a while since I've seen a new 16ga shotgun in person.
Then again, you can pick up nice Browning Auto 5:s in 16ga for little over $100 whereas 12ga starts at about $400, so there's a silver lining in near-obsolescence...