Cafe to just work or hang-out in Rome?

Italy is awesome for many things but I miss being able to work or hang-out for hours in a cafe without feeling the need to rush out (as is the case for most cafes and bars in Italy).

My question, does anyone know a place in Rome to just sit and relax and work (hopefully with an electric outlet for the laptop)? of course I'll order something. bookstores maybe?

Thanks ahead!
- Kat