@Dollarhyde - The Big Gundown is similar, especially since it's Morricone, along with Bruno Nicolai's orchestra, Alessandroni on the guitar (not as much whistling on this album), and also Ella Dell'Orso vocals in some parts. It has it's own feel, including a full-on vocal number, but it fits in with the overall vibe of Morricone's other western scores really well. I recommend it if you are into his other work in this area.
Django is well-known for the theme song. It's a great listen, and covers a lot of ground as far as spaghetti western influences go. It's definitely in the same realm as above, and a quality album with some really good quieter moments mixed in.
[video]https://www.youtube.com/watch?v=hRs2UMseNe8[/video]
Also, the AMS reissues are so well done!