Feral is best for leveling IMO. This is what I did:
First 5 points into Ferocity. This makes your most important skills cheaper. A must have.
Next put 2 points into brutal impact. This helps our only CC skills a lot.
The next 3 points can go where you like. Feral Aggression is a good choice.
Then go 3 into Sharpened Claws. This will really up your damage. you'll feel it right away.
I then put 1 into Feral Charge and 1 into Feline Quickness.
From here you have some choices. I filled out Blood Frenzy, Predatory Strikes and Primal Fury. I found them all useful. Some don't put points into Primal Fury as they don't use Bear form much. I have a pretty high crit build so the points are well spent.
I love Savage Fury and Feral Faerie Fire. FFF in particular is awesome as it's a free cast. Use it often!
5 points in Heart of the Wild is a must!
There is much debate about weather Leader of the Pack is worth an extra point. I have it. 3% crit is great for only a point. Some like to go higher in the other trees.
Here's my build:
http://www.wowhead.com/talent/?MzLVhoZxGMscrdtV
It's a pretty standard Druid build.
Just a couple other tips that I've learned.
Remember in Bear and Cat form, the DPS on your weapon is meaningless. You want as many stats as possible. +AGI, +STR add to our DPS, AGI adds to crit chance. STR gets a 20% bonus when in cat form when you have 5 points in Heart of the Wild and STAM gets the 20% bonus when in Bear form. INT and SPIRIT are also useful.
Look for items that are "of the tiger". These have both STR and AGI.
Bear form is wonderful for soloing elites and higher level mobs. Until about 40 or so you should be able to solo elites 1 or 2 levels higher than you.
Cat form should be how you level most of the time. Very effecient quick killing power.
If you plan on doing instances, most people will want you to heal, which you can very well. I'd recommend getting a second set of gear that has +INT or +SPIRIT.
I've had a blast leveling my druid. Just dinged 57 this morning. They are wonderously versatile and great soloers as well as one of the best party classes in the game.