Yeah Helm is a must considering headshots are a priority when a dwarf is down. If using metal armor I skip breastplates because they are so heavy if the dwarf isn't a skilled armor user. Set uniforms to replace if you are sure you have all of the gear to ensure the dwarf actually wears everything he has assigned rather than just a helm and vest.
I generally go mail shirt, gauntlet, greaves, helm, high boot, wood shield for my melee dwarves. Mail shirt wont stop bruising or blunt attacks very well, but if a dwarf is encumbered he will be attacking and dodging far less and will be hit much more and will be far less effective. I think my setup is actually on the heavy side and might be slowing them down a fair bit and only the chest is vulnerable to blunt attack, but they seem to dodge alright a lot of the time. I refuse to use danger rooms to boost armor user, if you're doing that they'll probably be alright with a mail shirt/breastplate combo. Steel is a short term priority upon embark, and my metalworking industry and mining are all focused on getting a few suits of it out as soon as space has been cleared for the necessary farms, stockpiles and workshops. Half the fun is trying to streamline the embark to get a fully armored squad out behind a moat and stockade in personal record time.
My archers and justice dwarves just get leather (the fortress guard might need chase a mischievous dwarf or two down and need to travel light). So thats leather armor, leggings, helm, high boot, wood shield, any crossbow. Not really bothered with anything else at it doesn't provide armor and will only make the dwarves run around trying to scab new higher quality socks and whathaveyou if any are produced rather than patrolling the ramparts and practicing.