There has been a lot of discussion about this, but the most recent threads devoted to the subject I can find are up to five years old, so maybe it's time to bring it up again. Now dwarves are rather unfortunately expendable at times, but the starting seven give the player a unique opportunity to design their skills sets, which directly influences the initial growth rate/capabilities of the fortress. So the question is how best to take advantage of that setup? Without going into detail for every skill, I will describe some of the choices I make and why, and welcome discussion about how other players here may do it differently.
My focus is on a balance between immediately useful/necessary skills, and useful skills which are hard to train in-game. I typically don't embark on evil biomes, but will occasionally remark on the differences this entails. I am going to just ignore skill rust as players have the option to turn it off and the whole rust-mitigation aspect complicates the discussion immensely. But feel free to bring it up of course.
SO.
1) Mechanic 5 / Diagnostician 5. This is the only dwarf I "reroll" for, I am looking for good scores in analytical ability (as the first priority, both skills depend on this trait), intuition, and memory. He should preferably not be weak as he will be lifting a lot of stone early on. Diagnostician is something that might come along later with migrants, but might very well not, and your entire hospital line depends on it. It's not easy to train without purposely injuring your dwarves. Mechanic has a good synergy and gives your doctor something to do in the meantime, the mechanisms are needed for initial defense (traps and bridges) and will be the mainstay of your economy for some time.
2) Mason 5 / Building Designer 5. It's handy to have these together, as this dwarf can now single-handedly construct stone draw-bridges, which are of immense value to defense. One can argue that mason doesnt need to be that high as he will level it up fairly quickly (spam block construction), but I like to be quick with my first masonic items and its convenient if they arent all super low value (doors, tables, thrones for your first dwarves, and get those bridges up asap). This dwarf should be strong or at the very least NOT weak.
3 + 4) 2x Miner (0 ranks if non-evil, 5 if evil), Armorsmith 1 for one and Weaponsmith 1 for the other. I then use the remaining ranks on weapon skills (priority) and dodging. Never spend skill points in mining unless you absolutely must dig quickly, you will be legendary before any other dwarf even gets a chance to mood. These dwarves might become legendary smiths, but otherwise they are going to go into the military as soon as the initial fort is constructed and we have some migrants to replace them on the digging. They should preferably have good traits for military servitude (iron will, rapid healing, good physical attributes especially endurance).
5) Teacher 5 / Axedwarf 5 . Something new Ive been trying. Teacher seems a bit harder to train and more valuable to have in the beginning. This guy immediately gets carpentry and wood-cutting turned on, and will chop wood and make a few items for the fort in the beginning. He might mood into legendary carpentry, and if you are lucky you will get an artefact hatch which can be a first line of defense for FBs. Later on a migrant can be the full time carpenter, this is a skill which quickly goes to legendary just making barrels from 0 ranks. This frees up our teacher to begin training some migrants / the miners. I've considered having him learn a defense skill instead, but it seems to me that weapon skill is the most important so...
6) Weaponsmith 5. He doesn't need any other skills, get him into a magma forge asap and start cranking out cheap weapons.
7) Armorsmith 5. Same thing as the weaponsmith, tho you might consider Growing 5 as an additional skill for evil biomes where caravans and especially migrants are not guaranteed. Otherwise farming is stupidly broken and food is not an issue. Growing goes on this guy because he is slightly easier to train than the weaponsmith. One thing which you should not do is double these two smithing jobs on the same dwarf. If they dont get a mood, you are going to need to focus on training for a long time and its counterproductive to have one dwarf try to do both tasks.
I used to bring a broker but frankly it's not needed. In sufficiently evil biomes you arent going to see many caravans/migrants anyhow, and if you do, you are guaranteed to find a dwarf with strong relevant social skills, eventually one with Judge of Character (which seems to not really improve significantly with more ranks). Appraisal auto-trains to highly effective levels after the you open the trade screen with the first large caravan. Before then, just trade surplus mechanisms (especially masterwork) for whatever you really need and you will be fine. Trading and economy in general is broken as hell, so even without this ease of building a broker post-embark, you are going to be just fine. Not bringing a broker has the advantage that you get to select him from migrants AFTER your expedition leader is chosen. If you build a broker, he invariable becomes leader and I find that half the time this asshole is stuck in a meeting and a non-broker dwarf has to do his job anyhow or you miss the caravan. Really. Annoying.
Things that people often train but they don't need to.
Mining (unless evil biome, see above)
Carpentry
Wood Cutting
Brewing (bring booze, skill here only effects time not stack size, you will be fine)
Growing (unless in very dangerous biome) you will be swimming in food, its stupid
Herbalist (same thing as growing, food is not an issue)
I find with this kind of build, I have more than enough embark points left over to tank up on all booze, increase seed stockpiles somewhat (in case of early mistake of stupid planting when season is too short), get some wardogs, a couple cats, a bunch of random food, and even splurge on two shearable pack-animals if I want to. I dont bring any of those last embark items which I can quickly make myself.