Thanks for the replies.
I may not actually need any additional packages from contrib or
non-free. But I hope I am not missing anything like proprietary
hardware drivers, or add-ins required to play proprietary media formats,
for example.
I did try to install in expert text mode first, but when it asked which kernel should be installed, I decided to let the install program decide that, so I re-did the install using the default text install mode.
And as for the freeness of Debian: that's why I am using it. I strongly support Debian, EFF, RMS, etc.