Something to keep in mind when deciding what classes/races to play.
Play what is fun to you. Have you sons play what is fun for them. Change your tactics accordingly in order to wipe out what you want to wipe out.
Although most people will advise you to play a traditional tank/healer/buffer/dps group, those groups don't work unless everybody is playing what they're enjoying. Chances of you and your sons each getting the class they want is pretty slim. Forcing your sons to play something they don't want to play means you're dooming yourself to boredom or worse. Even if you decide to play a class you don't really want to play but do it for the good of the team all you'll do is burn out soon.
Some non-traditional groups I've been a part of (and had fun at):
Wizard, wizard, wizard, rogue, paladin.
Mage, mage, mage, necromancer, beastlord.
Mage, chanter, druid.
Ranger, mage, mage, mage, rogue.
Paladin, shadow knight, necromancer.
IMO, any group can work if the people behind the toons adjust their tactics accordingly. Granted a group may not be able to take on the latest and greatest content but playing a class you like in a slightly less challenging zone is better than playing a class you don't like anywhere.