I've been leeching off my wife's ign insider account for a while now. Trailers are okay, but I prefer to download extended gameplay videos or behind the scenes stuff that is longer than the typical trailer. These videos are often in the 120MB - 600MB range, but the d/l from ign is pretty fast, and I can queue up a dozen at a time.
My laptop won't play the 720p videos smoothly, but I use mediacenter on the 360 and it is pure eye candy on the 60-inch sxrd. I doubt I ever would have purchased my own membership, but I am happy to exploit hers.