That is total CRAP. I have done over 12GB in one day in the past (last month). If I had Time Warner, I'd be switching to another ISP.
Verizon DSL isn't the greatest, but I have yet to get hassled about what I am downloading and/or how much bandwidth I am consuming. I also read an article from the CEO or something that mentioned that they will not be snooping on their customers traffic, so that's a bonus.