Try Charis SIL[0].

[0]: http://scripts.sil.org/charissilfont

Linux Libertine. http://www.linuxlibertine.org/

Hate to be that guy, but Computer Modern [1].

Out of TTF "natives" check out DejaVu Serif [2] and Droid Serif [3]. I've read countless ebooks set in the later.

[1] https://en.wikipedia.org/wiki/Computer_Modern

[2] http://dejavu-fonts.org/wiki/Main_Page

[3] http://www.droidfonts.com/info/droid-serif-fonts/

I'm partial to Serif myself, so I know what you mean :-)

In addition to Droid Serif, Liberation serif and Linux Libertine and Gentium recommended here, check out PT Serif also. Very readable on high resolutions and medium body fonts...

All these sets below, are complete (R, SC, B ,IT, B+IT...) fonts AFAIK.

http://www.fontsquirrel.com/fonts/pt-serif

Gandhi Serif, on the other hand makes excellent compliment to PT Serif as a beautiful heading font!

http://www.fontsquirrel.com/fonts/gandhi-serif

I also use Alegreya a lot.....

http://www.fontsquirrel.com/fonts/alegreya

In addition, these sets below, are complete (R, SC, B ,IT, B+IT...) fonts AFAIK.

http://www.dafont.com/justus.font

http://www.fontsquirrel.com/fonts/Latin-Modern-Roman

http://www.fontsquirrel.com/fonts/TeX-Gyre-Schola

http://www.fontsquirrel.com/fonts/TeX-Gyre-Bonum -- Bookman clone.

These are not complete, but they are close relatives.

http://www.fontsquirrel.com/fonts/Theano-Didot

http://www.fontsquirrel.com/foundry/Alexey-Kryukov

http://www.fontsquirrel.com/fonts/Old-Standard-TT

http://www.fontsquirrel.com/fonts/Bentham

http://www.fontsquirrel.com/fonts/DubielPlain

http://www.fontsquirrel.com/fonts/Theano-Modern

Enjoy!

Liberation Serif. Great for writing reports.

Gentium