What is the best class to use?

There is no "best class" as such - your choice of class should be purely based on your own preference, as you should be able to finish the game with any class. But the easiest class to play would probably be a fighter, as there isn't much to it. Being a fighter doesn't involve any spells, which means it is very easy for new players to use. My first character was a Paladin, and I didn't have a high enough wisdom to cast spells. But in the end it didn't make a huge amount of difference because as you level up, you get stronger. So choose your class on what you want to do (cast spells, be an absolute tank, sneak around etc.).

I'd say..... it depends on what is the most fun for you. I find wizards to be complex sometimes.... rogues are fun to sneak around and stuff.... fighters are pretty simple. They have good armor, good damage, etc..
They're the most balanced/easy to play I think. Wizards have nice armor if they're buffed. However, they're restricted to cloth armor unless you get the feat to wear heavy armor which screws up spell casting. When I first played, I went with the fighter. Wizard's spells don't do that much damage in the beginning of the game. However, when they're level 40, they kick butt. There's no "best class" however there are balanced ones. My favorite is wizard. I find them more fun than a fighter. You just pick what's most fun for you. If a fighter is boring, the game won't be fun. Then there'd be no point in playing the game. That's why they put so many classes in the game ;)

It's basicly up to you. If you like to kill fastthen a tank, if youl iked ranged stuff a wiz/ cleric, sneak around with a rogue ( yet they are EVERYWHERE) or have a super good defence with a guardian fighter enjoy!!