Well, in my work, that move from 16 to 32 GB was hugely helpful. But that included running a bunch of development environments (Eclipse, SQL Server, Microsoft .NET, etc).
On my home PC, that 32 GB that I have serves no useful purpose. I've noticed a speed jump on laptops when you go from 4 to 8 GB. But I'm not sure if that's due to more memory or the fact that with two sticks, it runs in the "dual" 128 bit mode.