BitTorrent is great for large downloads. As others have said, it's simple python, and very basic and not adware at all. What's nice about it is it's "swarming" p2p nature with download speeds tied to upload speeds. As soon as you begin downloading a file, any chunk of the file you've got is available to send to other people. The more you send, the faster you can download. Each part is checksummed, and the whole thing is checksummed once you get it, so the files are downloaded correctly. It's a great system, and a very lightweight install.

Matthew