Early Heart was definitely influenced by Led Zeppelin; they've covered a number of Zeppelin songs, so it's pretty clear that they're an influence. Plus, just listen to Ann's singing; she's like a female Robert Plant. There's no question that a lot of her delivery comes from his style.
"These Dreams" was a revelation to me, in a couple of ways. First, I didn't realize that Nancy sang lead vocals on any of their songs. I always thought it was Ann. I even have half a dozen Heart albums, but unlike with many bands, I didn't really dig through the liner notes. The other thing is that this is the first time I thought Nancy was kinda hot. When Heart first hit the scene, a lot of people talked about the band with the two hot girl singers, but to be honest, I didn't really think much of them. If you're hot anyway, that's great, but in every picture I saw, they were striking poses and making "sexy" faces and shit, and it was a turn-off. With the advent of video, you got to see what artists really looked like (kinda), and, well I was impressed. I think Nancy has actually gotten hotter over time, while I think it's fair to say that time hasn't been as kind to Ann.