I'm going to roll a random die - 1d10+1 using the En World die roller. That's the level. Go through each edition and, we'll use fighter, tell me what choices I can make to make my character more specialized at that level.
7, huh? Not a bad level in any ed.
AD&D 1e, pre-UA: You can choose to be of just about any race, but if you choose halfling, for instance, you never made it to 7th level. So the mere fact of being a 7th level fighter means you're probably human. Weapon and armor 'choice' (though really, if you go for anything other than Platemail & Sheild and Longsword, you're a chump, because most magic weapons are swords, and most magic swords are longswords, and Plate & shield gives you the best AC).
AD&D 1e, post-UA: Add Weapon Specialization. Now your weapon choice matters, because it's magic longswords, or quizinart of doom dual-wielding double-specialized hand axes or double-bow-specialization.
AD&D 1e, 'survival guides': Add non-weapon proficiencies to your list of trivial customization choices.
AD&D 2e: Add choice of kits. Level limits have been raised, so more races are possible for a 7th level fighter - maybe even all of them, I don't recall the whole chart.
3e: You can now be of any race, though human and half-orc are particularly good, and gnome and halfling rather poor. As a 7th level fighter you have (coincidentaly) 7 feats (2 at 1st, one at 2nd, one at 3rd, one at 4th, and 2 at 6th). You have 20+10x(INT mod) skill ranks (ie, probably 20) to distribute to a rather puny skill list, with 10 ranks being competent for level 7. Weapon choice matters a little bit more because there's no random chart weighting things in favor of the longsword, though that Spiked Chain looks pretty goofy, but mechanically quite good. Depending on your feat and weapon choices you might be a high-damage melee type, pretty good archer, or area-denial specialist making multiple AoOs every round against anything w/in 10' of you (20' with an Enlarge spells from a friendly caster or potion).
4e: You can be of any race, Human, Dragonborn, Dwarf, and half-orc are particularly good choices, halfling has a slight disadvantage. Weapon choices is still meaningful, but armor choice is a no-brainer. To shield or not to shield is a rather significant choice. As a 7th level fighter, you get to choose 2 at-will attack exploits, 3 encounter attack exploits, 2 daily attack exploits, and 2 utility exploits, you also get 4 feats. You can choose 3 skills from a smaller list of consolidated skills (though still a paltry class skill list), and you're competent with all 3 throughout your career. A feat will buy you similar competency in an additional skill that needn't be on your class list. You can also choose one or more backgrounds, and a Theme.