Number of hops is a terrible way of determining which mirrors to use. Here are some of the things I take into consideration:
Pipe size
Some servers, such as nasa's, have a really fat pipe. Even if it's a few extra hops, a server with a bigger network connection will often provide a happier, faster download experience.
Users allowed
When using FTP servers, there are some servers that are really fast, but quickly fill up. Such as orst.edu. Don't waste your time slurping from them unless you have a good reason to.
Protocol
My first choices are usually certain FTP servers, but my I always make sure to have a couple HTTP servers in at the end. Why? Because they're less likely to be "full" and not accepting users.
Lastly, location
I prefer to measure distance by ping latency instead of hops, it's a truer measure of internet distance. A parallel would be, if you're in a village on a main road, a city 200 miles away might be effectively closer than the village 20 miles away across roadless swamps.