I don't know why Maybe the hosts you're downloading from have heaps of upload slots open & so you're only getting a tiny bit of their bandwidth? Maybe they're not really T1 or T3...people sometimes set their LW's speed to higher than it really is. If you're only downloading from a single host, things will be slower than if you were downloading from multiple hosts. Search for the movies again, find the ones you're downloading. Right click the file > search more > get more results...see if you can speed things up with a couple more hosts.

If you can download a song at 180 KB/s then at least you know you're capable of downloading at a decent speed.

Those magnetmix files are just a bit of a test, often they'll download really slowly if an ISP is throttling bandwidth. Did you disable The Shield when you tried to view the magnetmix page? Try another browser if you like, but it's probably not worth it if you know that you can achieve good speeds.