Today, Philadelphians go to the polls to pick a new mayor, capping a record-setting, $25 million campaign to succeed Edward G. Rendell. Finally, voters will get a chance to choose between two men they have seen often on TV commercials and at neighborhood forums over the last year: Democrat John F. Street and Republican Sam Katz.

The nail-biter of a mayor's race has gained national attention and overshadowed other contests in the region.

In Philadelphia, voters also will elect 17 members of City Council, along with judges, a sheriff, a register of wills, three city commissioners, and other row offices. A ballot question asks voters whether they want to give the mayor more authority over the city's Board of Education.

In the Pennsylvania suburbs, among the hundreds of slots to be filled - from sheriff to school board to coroner - voters will pick new county commissioners and district attorneys, decide questions about open space, and select judges.

The highest-profile races in Montgomery County are for county commissioner and district attorney. In Bucks County, the race focuses on county commissioner and coroner.

Three townships in Chester County - Willistown, East Marlborough and West Vincent - are seeking approval to raise taxes to buy open space, as are two towns in Bucks - Buckingham and Solebury. Three of five slots are up for grabs on the Delaware County Council, which has had no Democrats for the last 24 years.

In New Jersey, all 80 state Assembly seats are open. Ballot questions include a $500 million transportation initiative, changes to state prison funding, and open-space issues. Burlington, Camden and Gloucester Counties all have freeholder positions up for election.

Polls in Pennsylvania and New Jersey are open from 7 a.m. to 8 p.m.

With pollsters rating the Philadelphia mayoral contest today a toss-up, District Attorney Lynne M. Abraham and Frederick L. Voigt, executive director of the Committee of Seventy, yesterday urged all eligible voters to go to the polls early and report any suspicious behavior.

There are 988,005 registered voters in Philadelphia, with Democrats outnumbering Republicans 736,692 to 191,742 or about 4-1. Nonpartisan voters number 50,130; Libertarians, 2,551; registered minor-party voters include 972 for the Constitutional Party, 276 for the Consumer Party, and 268 for the Reform Party. The remaining 5,374 voters list 50 other smaller-party affiliations.

Abraham said that to make the voting process "as fair as possible," she would increase the number of assistant district attorneys on the street and at 11 election courts set up in police districts around the city. Voigt said the Committee of Seventy, a nonpartisan election watchdog group, plans to put nearly 100 volunteers at polling places to answer voter questions and investigate complaints.

Rain is in the forecast for at least part of the day, a factor that Abraham said could affect turnout.

"Those people who wait until they get home from work to go out to vote - instead of getting up 10 minutes earlier in the morning - may decide unfortunately not to go out and vote, if it's raining too hard at that time," she said.

Those who make it to any of the city's 1,681 polling places will have a choice between three men vying for the $135,000-a-year mayor's job:

There is Street, 56, a longtime figure in local Democratic politics who rose to the presidency of City Council and has made his years of government experience the hallmark of his campaign. And there is Katz, 49, a Republican entrepreneur-turned-politician who wants to shrink the city's wage tax as a means to keep people and businesses in town.

Yesterday, Street kept up a busy schedule, greeting voters at 8:20 a.m. with Mayor Rendell in Center City, meeting veterans in the afternoon, and campaigning with City Councilman Frank DiCicco in South Philadelphia at dinnertime. Katz's public schedule included greeting voters at rush hour in Center City and appearing at the Taste of South Philadelphia event at the First Union Center in the evening.

Though he has been less visible on the campaign trail, there is a third candidate, too: John P. McDermott, a 48-year-old self-employed salesman from Northeast Philadelphia who represents the antiabortion Constitutional Party.

Some voters have already registered their opinion. Of 5,910 absentee ballots requested in Philadelphia, 4,517 were returned by last week's deadline, according to Dennis Kelly, the city's supervisor of elections. That represents a 76 percent return rate.

The absentee ballots are sorted by ward and division, then delivered to police districts. This morning, officers will take the ballots to polling places, where they are opened and tallied.

Many of the absentee voters are the sick or disabled, Kelly said.

"Most of the polling places are inaccessible because of the very machines themselves," Kelly said. "If you're sitting in a wheelchair, it's hard to reach those levers."

Voigt urged voters who encounter problems at the polls to go to one of the city election courts, staffed by Common Pleas Court judges in the police districts.

Voigt said that if a would-be voter's address does not match his voter registration card, he will be referred to election court. There, a judge will require him to simply "affirm," or swear, that the address is correct. Then the person will be allowed to vote.

"In this country we favor a person's right to vote as being paramount," Abraham explained. "Therefore, at the polling place there will be few, if any, challenges, to a person's residency and identity."

Voters with questions or problems today can call: the Committee of Seventy at 215-557-3600, or the Philadelphia Election Board at 215-686-1590.