Always read the small print, most take steps or avoid answering the question.
So much so for unlimited, it dont exist, you get what you pay for.
For 100Gb/month any Entanet service provider is worth a try, i am with http://www.adsl24.co.uk £20/month 30Gb day and 300Gb off peak, no throttling like most others and you know exactly what you are getting, no small print everything laid on the table.