I've never used Steam before and I was just wondering, is a download speed of 700 KB/s normal?
Admittedly, this wouldn't be as bad if Shogun 2 wasn't 18 GB . . .
Steam's DL speeds depend on server load, your own internet speeds, and anything else you're doing online at the time. Obviously if you're trying to DL from Steam, play World of Warcraft, and stream from Netflix at the same time, you're going to be having some problems.
What's your typical download speed for non-Steam downloads?
You can try changing to a different download server if you suspect the problem is on Steam's end. Go to the Steam dropdown menu -> Settings -> Downloads + Cloud. There's an option there to change your download region. I've heard some people have good luck in picking regions where there's currently lower traffic (due to the time of day) or just a lower population on that server in general.
700KB/s is respectable to me at least, but again, it depends on what kind of speeds you get normally. Typically my Steam downloads are slower than that.