It's really hard to say what would make the best duo...much less best class, period. In my opinion you just have to connect with the class. Personally, I started off a Shadowknight, but once I got to around level 20, I just didn't like what the SK did. Granted, Harm Touch is a nice ability, esp since it grows with you, and pet classes are nice, but I just couldn't find a groove with it. Then I tried another pet class, the Beastlord...again, just couldn't find a niche. Then I tried a pure caster, but I just couldn't deal with not having any real fighting ability. Long story short, I found my groove with the Monk and Berserker, and I play both really well.
But in general:
-Clerics are always nice to have considering they have the better healing spells, as well as get them sooner.
-Enchanters are always in demand because of their crowd control. It's good to know that when the fit hits the shan, they can come through in a pinch.
-Mages and Wizards are great for their nuke spells and ability to make pets uber (advanced appology, I always get Mages and Wizzys confused, that's why I lumped them like that).
-Shamans and Druids are your buffmeisters. Spirit of Wolf, Harnessing of Spirit, etc. You name it, one of them prolly has it. Clerics also have great Hit Point and Armor Class spells.
-Necromancers do awesome Damage over Time. Their ability to steal life from creatures, then convert their own life into mana for someone else is just sic.
-Paladins and Shadownights are good classes because they make good substitute Tanks. Paladins can off-heal and are good at Paci-Pulling. Shadowknights are another pet class, as well as having access to most, if not all, the necro spells, allbeit at later levels.
-Warriors are considered THE Tank class. They are the ones who go up front and get beat on by the creature. Then again, their HP and AC is virtually uncomparable.
-Monks, Rogues, Berserkers, and Rangers are the guys who'll come in and do light/medium damage while the Tank is getting beat on. Though their damage per attack is far less than that of your Warrior, they'll prolly get at lest 2 or 3 times more attacks than the Warrior, so it's a good balance. Rangers are also great trackers, as well as they have access to Druid spells, though like SK's at later levels. Rogues are evil little guys because they can come from behind and do some truly wicked damage with their backstab. Berserkers are just insane with their Snare, Stun, and Frenzy abilities. Monks are a well-rounded class with a variety of abilities and attacks, though more known for their kicks and Feign Death.
-Beastlords are another fun class to play. They are considered one of the best pet classes as well as being well-rounded fighters. To be honest, besides pet and self buffs, not too sure what all their spells encompass.
-Bards are an interesting class. In my opinion, they are a little bit of everyone. Their songs mimic a HUGE variety of spells, and they can go in and do some added damage if need be. Though in the groups I've been in, they usually just stand between the casters and fighters and mix songs that help out everyone.
Hope this helps you out some. Keep in mind, I'm not saying this is exactly how the classes are played, but how I've seen them played more often then not.
Edited for grammar. Hukt on fonix, ya know?
Edited, Sun Mar 28 02:00:09 2004 by psychojester