The problem with Puck and Rachel is that they never really liked each other- Puck thought she'd be his jewish girlfriend to please his family while he screwed around with Santana and everyone else. He can't commit, and Rachel wouldn't be able to handle that. Rachel, on her part, only agreed to try and forget Finn, and that didn't work out. So Nay to them.
Jesse and Rachel, in many ways, are very compatible- they're both driven, competitive, insanely talented and have a flair for the dramatic. However, Jesse has proven in the last episode that he is a coward- despite certainly having feelings for Rachel, he chooses to break things off with her and the club in a way to ensure that he'll be welcomed back to Vocal Adrenaline as a hero, whereas had he broken up with her in a more decent why he might have been shunned for liking her. His need to win overlaps any other feeling he may have- which is why he eggs Rachel and returns to Vocal Adrenaline. On Rachel's part, she may be many things, but she has never proven to be a coward- she stands up for what she believes in, (which may get her in trouble), but doesn't back down and goes to great lengths to help those and herself, if necessary. She wouldn't be able to tolerate Jesse's cowardice in this issue. So Nay to them as well.
Which is why I support Finn and Rachel. Sure, Finn's a bit of an idiot- but he's a good-hearted idiot nonetheless. We've seen him grow throughout the show- and though he doesn't make the best decisions, he always follows through with them, learns his lesson, and improves somehow. His initial attraction with Rachel was underscored by his preocupation at the time with Football, and not seeming gay for joining Glee club- however, by this time, we have seen that he has truly become dedicated to the club, and his fellow members. He breaks up with Rachel the first time because he's just ended a long relationship with Quinn, and isn't quite ready to jump into the sort of relationship that Rachel demands. But now, we've seen his feelings for Rachel are quite thorough, as he told her in "Laryngitis". He's finally ready to be what Rachel needs.
As for Rachel, she was at fault for their first break-up too, of course. She rushed into it too quickly (I mean, seriously, Calendars? I'd be freaked out too.) This is due of course to her long-time crush on him from pretty much the first meeting- she's inexperienced, and giddy with the thought of being with Finn- so she lets her emotions take over and so it ends. But now, however, she's grown up a bit- and we've seen her dedication to Finn, despite everything, remains.
Which is why, to conclude, I say Yay to Finn and Rachel. X3 heart