Throttling is a painful way of life for me too. After about 65 MB, I'm throttled down to about 65 Kbps. I have wireless broadband sent to me from a tower about 6 miles away and they claim they have no choice. Don't know if I believe that, but since I would be sitting here on dial-up without them, I can't complain. Lan, a download of that size would take every bit of 3 or 4 days for me too.
Sounds like you have a similar situation to mine. I used to have a wireless/cable arrangement, but the small ISP went out of business. The cable company won't wire our place even though other people around us have cable already. The satellite people took one look at our 3-story house and said, "Nope, trees would be in the way." What?? So stuck with old wiring and DSL. Still, I AM grateful I don't have dial-up, but sometimes ...!
I've called the ISP and complained a few times when I've noticed a slow-down, but they tell me that as long as I'm getting within 80% of expected, they won't do anything. A couple of times, though, they did reset me when it was lower.
Traveler, you should have seen my husband go nose to nose with the cable people. He threatened calling in authorities, but if you knew Alaskan politics, you'd know how little that means!
I'll post a question about Steam's download sites over in Glitches. Thanks, guys! In the meantime, I'll just try to be patient. <sigh>