CBS News found notable problems in roughly 15 states, although all were sporadic. Most of the issues came early in the morning when poll workers had problems starting up their new electronic voting machines.
A number of polling places stayed open later in half a dozen states as a result of voting machine glitches, but none of the delays seem to have had an impact on final election results.
A judge turned down Colorado Democrats' request to keep polls in Denver open for two extra hours after balky computers, the longest statewide ballot in decades and unfamiliar new voting machines delayed voting for up to three hours.
Democratic Party attorney David Fine said he did not know whether the decision would be appealed.
State GOP spokesman Bryant Adams had called the request "outrageous" and unnecessary. Adams said anyone in line by the scheduled 7 p.m. closing time would be allowed to vote, and he accused Democrats of trying to win the election in the courts rather than at the ballot box.
There have also been claims of attempted voter intimidation in Virginia, in the midst of a heated Senate race between Republican Senator George Allen and Democratic challenger Jim Webb.
Jean Jensen, secretary of the Board of Elections, said that her office has forwarded to the state and federal officials reports of several instances of phone calls to voters that apparently were aimed at misleading voters into staying home on Election Day or leading them to the wrong polling place.
In Arlington County, resident Timothy Daly said he got a phone message Sunday, said to be from the "Virginia Elections Commission," telling him he was registered to vote in New York so he couldn't vote in Virginia.
"If you do show up, you will be charged criminally," said the message, the text of which appeared on Daly's affidavit to the Board of Elections.
The Webb campaign said in a statement that the calls were intended to confuse and discourage Virginians from voting.
Chris LaCivita, a senior consultant to the Allen campaign, said the calls weren't originating from the GOP.
(The Webb campaign's website posted what it says is a recording of the phone message Daly received. Listen here.)
"If something is going on that worries and alarms voters enough that I'm contacted to look into it, I have a responsibility to do that," she said.
CBS News has learned that the FBI is looking at the allegations to see if the calls amount to a federal crime.
Clay Landa, an analyst with the election board, called the complaints anecdotal and difficult to confirm. A state elections official said early reports from around the state indicated an extraordinarily high turnout for a midterm election – with perhaps 65 percent of registered voters expected to cast ballots.
With a third of Americans voting on new equipment and voters navigating new registration databases and changing ID rules, election watchdogs worried about polling problems even before the voting began.
The Justice Department deployed hundreds of poll watchers 69 jurisdictions in 22 states to keep an eye out for problems.
Jonah Goldman of the Lawyers' Committee for Civil Rights Under Law characterized the troubles as systematic - small problems that cropped up across the nation but didn't become catastrophic breakdowns in any one location. He said a national Election Protection coalition logged 9,000 calls by noon on its hotline.
"Lots of fender benders, but no major tie-ups," said Doug Chapin, director of Electionline.org, a nonpartisan group that tracks voting changes. "It's been a steady drumbeat but nothing that rises to the level of `This could compromise the results."'
CBS News producer Stephanie Lambidakis reports that calls and e-mails to the Justice Department's voter hotline are "surprisingly low," according to a Justice official. Slightly more than 200 complaints have been logged, compared to 1,200 in the 2004 presidential election.
CBS News has also learned that the U.S. Attorneys' offices are reporting a similarly low call volume.
In Cleveland, voters rolled their eyes as election workers fumbled with new touchscreen machines that they couldn't get to start properly until about 10 minutes after polls opened.
"We got five machines — one of them's got to work," said Willette Scullank, a trouble shooter from the Cuyahoga County, Ohio, elections board.
Tempers did flare in Kentucky. A poll worker was arrested and charged withfor allegedly choking a voter and pushing him out the door, officials said.
It apparently started as a dispute between the two over marking the ballot, said Lt. Col. Carl Yates of the Jefferson County sheriff's office.
The voter told poll worker Jeffery Steitz that he didn't want to vote in a judicial election because he didn't know enough about the candidates, but Steitz told him he had to vote in the race anyway, Yates said.
Election officials in Delaware County, Indiana, extended voting hours because voters initially could not cast ballots in 75 precincts. Karen Wenger, the country clerk, said the cards that activate the push-button machines were programmed incorrectly but the problems were fixed by late morning.
In Indiana's Marion County, about 175 of 914 precincts turned to paper because poll workers didn't know how to run the machines, said Marion County Clerk Doris Ann Sadler. She said it could take most of the day to fix all of the machine-related issues.
Pennsylvania's Lebanon County also extended polling hours because a programming error forced some voters to cast paper ballots.