Spaniard Fernando Alonso is shooting for his third straight F1 world title this year. (Mark Thompson/Getty Images)

As one era ended at the conclusion of the 2006 Formula One campaign, another one begins with the 2007 season.

Seven-time world champion Michael Schumacher of Germany, the greatest driver in the history of Formula One, retired at the end of 2006, paving the way for Spaniard Fernando Alonso to assert himself as the new king of the series.

Alonso fended off the challenge of Schumacher in 2006 to win his second straight world title for Renault. The young Spaniard joined McLaren in the off-season and will be looking to win his third straight drivers' title, while at the same time delivering McLaren its first constructors' crown since 1998.

Alonso wasn't the only marquee driver to change teams, as Kimi Raikkonen left McLaren to join Ferrari, where he replaces Schumacher. The Finn has come close to winning the drivers' title in the past — he finished second in 2003 and 2005 — and hopes that the Ferrari red can finally put him over the top.

Although there are no new teams on the grid this year, the race schedule has changed. The Belgian Grand Prix returns, while the European Grand Prix, held in Germany, and the San Marino Grand Prix, at Imola, Italy, have been dropped.

New rules this season stipulate that the two free practice sessions on Fridays of race weekends will be extended to 90 minutes from 60, and teams will be allowed to use only two cars in each of the sessions. Three were allowed last season.

Bridgestone will supply all the tires this season, after Michelin pulled out at the end of the 2006 campaign.

Here's a breakdown of the drivers to watch on this year's circuit.

THE FAVOURITES

Fernando Alonso (Spain)
Team: McLaren
Career wins: 15 Career podium finishes: 37
2006 result: World champion
The reigning two-time world champion begins a new chapter in his career with McLaren and will be looking to solidify his reputation as the best driver in the world. Alonso looked quick in winter testing and is eager to deliver McLaren its first drivers' title since 1999. Alonso combines consistency, speed and tactical shrewdness, and at 25 years old, he's on the verge of joining the sport's elite — only eight other drivers have ever won three world titles in the history of the sport. With Schumacher out of the picture, Alonso, the new king of Formula One, is this year's front-runner.

Kimi Raikkonen (Finland)
Team: Ferrari
Career wins: 9 Career podium finishes: 36
2006 result: Fifth overall
Talk about having big shoes to fill. Raikkonen, nicknamed the Iceman on account of his calm, cool and calculating race strategy, left McLaren after five years to join Ferrari, where he replaces Schumacher — so, no pressure then. He has a point to prove following a lacklustre 2006 season (he failed to win a single race last season after winning seven the year before). Raikkonen is widely regarded as the fastest driver in Formula One, but he's not as complete a driver as Alonso. The Finn is hoping the move to Ferrari proves to be the kick-start that his career needs.

ON THE RISE

Jenson Button won his first career F1 race last season. (Mark Thompson/Getty Images)

Jenson Button (Great Britain)
Team: Honda
Career wins: 1 Career podium finishes: 15
2006 result: Sixth overall

After years of failing to live up to his potential, Button had a breakout season in 2006 when he won the first race of his career, the Hungarian Grand Prix. The win, his first in 113 races, sparked a strong run by the silky-smooth British driver, who scored more points than anyone else — including Alonso and Schumacher — in the second half of 2006 to finish sixth overall. Button has already said, however, that Honda's new car is not quick enough to give him a realistic shot at the world title, which means he could be playing catch-up by the time summer rolls around.

Robert Kubica (Poland)
Team: BMW Sauber
Career wins: 0 Career podium finishes: 1
2006 result: 16th overall
Kubica became the first Polish driver to race in Formula One when he made his debut at last year's Hungarian Grand Prix. The Pole, who took over Jacques Villeneuve's spot on the team, ended up being disqualified in Budapest, but made up for it when he earned his first podium finish in only his third career race at the Italian Grand Prix a month later. Kubica finished the season strongly by posting back-to-back top-10 finishes in the final two races, marking him as one of the circuit's most promising young talents.

ON A SLIDE

Ralf Schumacher (Germany)
Team: Toyota
Career wins: 6 Career podium finishes: 27
2006 result: 10th overall
With big brother Michael retired, Ralf carries on the Schumacher name in Formula One. Ralf is on the hot spot, though, and 2007 will be a do-or-die year for the German who is out of contract at the end of the season. If Ralf wants a new deal — be it with Toyota or another team — he'll have to improve on a lacklustre 2006 campaign in which he recorded a single podium finish. Ralf has failed to impress since joining Toyota from Williams in 2005 and hasn't won a race for the Japanese automaker. His winless streak isn't likely to end this year.

Rubens Barrichello (Brazil)
Team: Honda
Career wins: 9 Career podium finishes: 61
2006 result: Seventh overall
For Barrichello, the grass wasn't greener on the other side. The Brazilian joined Honda last year after terminating his contract with Ferrari as the Italian outfit's No. 2 driver behind Michael Schumacher. It was supposed to mark a new chapter in his career, as he was finally out from under the shadow of the German legend. But Barrichello never really took off in his first season at Honda — his best results were a pair of fourth-place finishes — and he was outperformed by teammate Jenson Button throughout the campaign. Expect to see more of that in 2007.

THE DARK HORSES

With Fernando Alonso gone, Giancarlo Fisichella will lead the way for Renault this season. (Clive Rose/Getty Images)

Giancarlo Fisichella (Italy)
Team: Renault
Career wins: 3 Career podium finishes: 18
2006 result: Fourth overall

With Fernando Alonso leaving the team, the Renault torch has been passed to the Italian. Fisichella has a heavy burden to carry; with Alonso replaced by rookie Finn Heikki Kovalainen, it will be up to the Italian to lead the chase for Renault's third straight constructors' title. Fisichella had a strong 2006 season, winning the Malaysian Grand Prix en route to a fourth-place finish overall. He lacks Alonso's consistency, but the Italian has great pace, ability and flair. What's more, he's eager to prove himself as Renault's top driver with Alonso gone.

Felipe Massa (Brazil)
Team: Ferrari
Career wins: 2 Career podium finishes: 7
2006 result: Third overall
Massa enters the 2007 campaign with a great deal of confidence after firmly establishing himself at Ferrari last season. Massa earned the first two victories of his career during his first campaign with the Italian automaker, taking the checkered flag at the Turkish and Brazilian grands prix. Media attention will be focused on his new teammate, Kimi Raikkonen, but the Brazilian is a quality driver and has to be considered a serious title contender in 2007.