Another new dataset that might be of some interest to readers: The National Elections Across Democracy and Autocracy series:
The National Elections across Democracy and Autocracy (NELDA) dataset provides detailed information on all election events from 1960-2006. To be included, elections must be for a national executive figure, such as a president, or for a national legislative body, such as a parliament, legislature, constituent assembly, or other directly elected representative bodies. In order for an election to be included, voters must directly elect the person or persons appearing on the ballot to the national post in question. Voting must also be direct, or "by the people" in the sense that mass voting takes place. That voting is "by the people" does not imply anything about the extent of the franchise: some regimes may construe this to mean a small portion of the population. However, when voting takes place by committee, institution or a coterie, the "election" is not included. By-elections are not counted as elections for the purpose of this project, unless they take the form of midterm elections occurring within a pre-established schedule. In federal systems, only elections to national-level bodies are included. Cases in which any portion of the seats in a national legislative body are filled through voting are included.
Beyond these basic requirements, elections may or may not be competitive, and may have any number of other ostensible flaws. In fact, this last feature of the dataset is what separates NELDA most clearly from other available datasets on elections.
That's from the overview. The actual data (in STATA and Excel formats) requires filling out a form here. There appears to be a glitch in the form right now, whereby "Other" is the only category of user that actually allows you to download the data.
UPDATE: Forgot to ht Monkey Cage.