Perfect ending or underdog tale?

Eli Manning and Tom Brady. The upstart quarterback with the famous last name and the three-time champion passer with the famous social life.

Tom Coughlin and Bill Belichick. The stiff, rejuvenated former taskmaster who has lived on the chopping block and the stiff, innovative game-planner looking for his fourth championship.

Plaxico Burress and Randy Moss. The lanky, physical veteran who has played hurt for five months and the lanky, polarizing receiver who set an NFL record for touchdown catches this season.

New York and Boston metropolitan areas. Enough said.

While a Super Bowl XLII matchup between Brady’s New England Patriots and Brett Favre’s Green Bay Packers might have drawn better ratings, a Patriots-New York Giants duel Feb. 3 in Glendale, Ariz., presents several intriguing subplots.

Before the Hype Machine gets cranked up Sunday when both teams are scheduled to arrive in the desert, here are five early story lines:

1. Patriots perfection — New England is the first team to win 18 games in a single season. The Patriots’ next task is joining the 1972 Miami Dolphins as the only team to finish the season perfect.

But since thrashing Buffalo 56-10 on Nov. 18, the Patriots’ average margin of victory has been 10.2 points, compared with 25.4 points in the first 10 games. New England rallied against Philadelphia, Baltimore and the Giants and labored against the Jets, Jacksonville and San Diego.

“I think you enter the season and you’re hoping to put together a bunch of great wins and you realize there’s challenges every step of the way,” Brady said. “We had a few letdowns or times where we didn’t play our best, but we overcame them.”

The difference is between New England and other teams, the Patriots figure things out in time to win.

But they may have left an opening for a hot team like the Giants.

2. Unlikely opponent — The Giants were not given much of a chance to reach the Super Bowl. Not after getting pounded by the Washington Redskins in Week 15. Not after the Giants needed a defensive touchdown to ignite a win at Buffalo.

The fifth-seeded Giants are perhaps the most unlikely NFC representative since the 1979 Rams advanced with a 9-7 regular season record. Los Angeles, coached by the memorable Ray Malavasi, lost to Pittsburgh 31-19.

Since the 12-team playoff system was introduced in 1990, Carolina (2003) and the Giants are the only NFC wild card qualifiers and the only two opening weekend playoff teams to win three postseason games.

“This is very satisfying,” defensive end Michael Strahan said. “The best thing would be to win the big one, but this is great. A lot of guys came up to me and told me how much I deserve this, but to be honest, I’m happier for them because they deserve it more.”

The Patriots have been installed as 12½”point favorites — the largest spread since New England was a 14-point underdog against St. Louis in the 2001 season and won 20-17.

3. Another Manning — Last year, it was finally Peyton Manning’s time to reach the Super Bowl and win the championship — in his eighth season.

Now it’s Eli’s turn. But who knew it would be this soon? The Mannings are the first brother duo to reach the Super Bowl.

“It’s exciting, but it’s not about me,” Eli said. “It’s about this whole team. … It’s just been a matter of getting hot at the right time. It feels good because this is what you work for.”

Entering the month, Eli’s claim to fame (besides being Peyton’s brother) was an 0-2 playoff record, maddening inconsistency and, in the third-to-last regular season game, an astounding 36 incompletions against the Redskins.

In the playoffs though, Efficient Eli has replaced Erratic Eli. Manning has outplayed three quarterbacks — Tampa Bay’s Jeff Garcia, Dallas’ Tony Romo and Green Bay’s Brett Favre — completing 62.4 of his passes for 599 yards, four touchdowns and no interceptions.

4. Defensive standouts — Five New England players were named to the All-Pro team: Brady, Moss, offensive tackle Matt Light, linebacker Mike Vrabel and cornerback Asante Samuel.

Zero Giants players were named.

But there are several defensive players on both teams who figure to have an impact on their teams’ chances … and not all are All-Pros or even Pro Bowl players.

Look at the rankings. Total defense — Patriots fourth, Giants seventh. Rush defense — Patriots 10th, Giants eighth. Pass defense — Patriots sixth, Giants 11th. Scoring defense — Patriots fourth, Giants 17th. Sacks — Patriots second, Giants first.

The Giants are led by middle linebacker Antonio Pierce, pass-rushers Osi Umenyiora, Justin Tuck and Strahan and, with two more weeks to get healthy, cornerbacks Sam Madison and Aaron Ross. The group was far more physical than Green Bay, holding the Packers to 28 yards.

New England has stars all over the field: Vrabel, Samuel, defensive Richard Seymour, nose tackle Vince Wilfork and reliable veterans like safety Rodney Harrison and Tedy Bruschi.

5. All Brady, all the time — The requirement to obtain a credential for Super Bowl Media Day — a week from today — is, well, have a pulse and a microphone. Brady will be the week’s most popular subject.

Brady was a great story when New England first reached the Super Bowl in 2001, the sixth-round pick thrust into the lineup when Drew Bledsoe was injured … and then not letting go of the job. And then he helped the Patriots upset the Rams with a last-minute scoring drive.

Six years and two more Super Bowl wins later, everything about Brady except for his play on the field will be probed by the non-sporting press.

Brady can join Terry Bradshaw and Joe Montana as the only quarterbacks to win four Super Bowl titles.

“It’s been an emotional season coming down the stretch, and it just feels like things just build and build and build,” Brady said. “I’m glad we have to week off to regroup a little bit and try to evaluate our game for one last performance. Every time I’ve played in the Super Bowl, I’ve cherished it, and it never gets old.”