The story so far: Despite various lurid tabloid stories about their previous jobs at a certain gentleman's club in London, Kandy Rain have made it through to the Final 24 with relatively little drama. Their performances of Pussycat Dolls' 'Don't Cha' and Oasis' 'Stop Crying Your Heart Out' impressed the judges, while their provocative outfits have helped them stick in viewers' memories. The story behind the name? "Kandy - because, you know it's bad for you, but you always want more. Rain - because we're here to leave a lasting impression." Pretty simple, really!
Chances of winning: In the short term, things look bright for the girl group, who seem like a fairly safe bet to make the Final 12. However, Louis's poor track record with girlbands, combined with the general public's lack of enthusiasm for the Groups category, will surely count against them.
The story so far: Formed at boot camp after being rejected as solo artists, Graziella, Shar and Shaniece united as Miss Frank at the request of the judges. Their performances of 'That's Life' and 'Wishing On A Star' went down well and packed more energy and natural charisma than many groups who have been together for years. What they lack in a traditional X Factor backstory, they make up for in enthusiasm and all three appear dedicated to making the group work.
Chances of winning: Graziella has quite a powerful personality, which may endear or, more likely, turn off the public, while her rapping interludes are unlikely to appeal to the X Factor demographic. It seems unlikely Louis would pick two girls bands, but even if he does, would he risk this edgy trio?
The story so far: After their first audition in Birmingham, where they sand Kanye West's 'Love Lockdown', Cheryl Cole described Harmony Hood as "fresh", "original" and claimed that she was "excited" about their potential. However, Ryan, Charlie, Yanique and Abigail's performance of U2's 'With or Without You' at boot camp didn't cut the mustard and it was only the withdrawal of Tru Colourz that allowed them into the Final 24. Like a budget Black Eyed Peas, or Liberty X with better singers, they would be a risky and surprise pick from the typically traditional Louis.
Chances of winning: After making the Final 24 by default, making the Final 12 in itself would be quite an achievement. They are slick and well-styled - check out their 'How Hood Are You' T-shirts - but they are still probably the rank outsiders in this category.
The story so far: Probably the group we know least about, De-Tour could be a surprise package or merely making up the numbers. Duo Paul and Philip have given gravelly vocalled renditions of Kings Of Leon's 'Use Somebody' and Paolo Nutini's 'Last Request' and are not too dissimilar to X Factor 2005 workmen-like rockers Journey South. Louis's apparent passion for rival duo John & Edward is, sadly, likely to count against them.
Chances of winning: If Louis does pick them for his Final 12, they will face stiff competition from The Boys and the Over-25s for female fans' affections. Duos do have a decent record in the competition (Same Difference, Journey South), but it would be quite a shock if these guys ended up triumphing.
The story so far: The main competition for Kandy Rain, Lauren Green, Amy Burrow, Lucy Graham and Laura Henderson are a group of cheeky girls who formed after working as cheerleaders in Leeds. Their performance of Lady GaGa's 'Let's Dance' in the auditions didn't sound the strongest vocally, but the fact that they could pull off a dance routine and appeared to understand what a girl group should look like, helped them through. Kimberly Walsh has apparently said she's a fan, but unfortunately for the girls her pal Cheryl isn't their mentor.
Chances of winning: We've seen very little of them and the tabloids' fascination with Kandy Rain may have influenced Louis's final decision. If he picks both, the Irish judge risks splitting fans like he did last year with Bad Lashes and Girlband.
The story so far: The most controversial act in the Final 24, hair-raising Dublin duo John & Edward have riled plenty of viewers with their cocky showmanship and unrivalled arrogance. Their versions of the Backstreet Boys' 'As Long As You Love Me' and OneRepublic's 'Apologise' were nothing special, but luckily for them Louis Walsh is the one man in the UK who enjoys their attitude. They certainly know something about performing and making an impact, and they could end up being the biggest story of the series.
Chances of winning: Virtually nil. However, the boys could go further than many suspect. Louis will dedicate plenty of time to the duo and Cowell's passionate dislike for the pair could grant them a McDonald brothers-esque run in the show.