Coming up with this list was tougher then I thought. Skyrim has a few excellent perks in it, some of which didn't make it here - mainly because their uses were either too focused on a single role - or they required a lot of investment for comparably little tradeoff. No need to keep droning on though - in no particular order, my version of the best ten perks in Skyrim is as follows:
Impact (40 Destruction) - Most dual-casted destruction spells stagger opponents. Not only is staggering an opponent cool and hilarious, but it buys you valuable time as a caster in order to make distance, or land a few more spells. Invaluable to any character that uses magic as its primary source of damage.
Mystic Binding (20 Conjuration) - Bound weapons do more damage. Not just more damage, a lot more damage. An early early level character can, at Conjuration 25, buy the bound sword spell, and have a ~20 damage one handed weapon. It escalates with Conjuration skill as well, so its always useful, never breaks, and gets stronger as you use it. Conjuration and One-Handed Weapons raise simultaneously while your using it (and raise quickly) all one-handed perks apply as if you're wielding a sword as well. The downside? You need to summon the sword before you fight, which can be annoying. The upside? You also get to summon minions, which are excellent sources of additional damage.
Silent Roll (Sneak 50) - While Sneaking, pressing (Alt by default) run will allow you to execute a silent roll forward. Good for closing gaps, requires a somewhat minimal amount of stamina (You can roll 20x with 200 stamina) and great for positioning for backstab multipliers, or just getting around enemies and dodging spells, or dragons breath, with some practice.
Assassin's Blade (Sneak 50) - Backstab multiplier increased to 15x. Coupled with Silent Roll this more or less assures you always kill your opponent with a successful backstab. Satisfying and sinister, this perk is easily the highest damage/investment perk in the game.
Power Shot (Archery 50) - Stagger opponents 50% of the time. This is to archers what Impact is to mages. Staggered opponents don't move or attack, buying you more time to finish them off.
Elemental Protection (Block 50) - 50% Fire, Frost, and Shock resist while blocking. Laugh at spell casters and dragons as they try to damage you with magic. Coupled with playing a Breton (25% magic resist by default) this perk literally assures you that you never have to worry about damaging spells or enchanted weapons ever again.
Everything in the Enchanting Tree - From more powerful enchantments, to being able to put TWO enchantments on a single item. The entire tree is worth investing in, as it gives you the maximum benefit out of every piece of equipment. A must have for anyone looking to get the most out of their character.
Mage Armor (Alteration 30) - The three levels of this perk gradually increase the amount of armor granted from alteration spells. If you're playing a pure mage, or meleeing in mage garb, this perk is for you. But much like Mystic binding, it requires you to buff yourself with armor spells before combat. Not hard to manage, but can be cumbersome to some players.
Fighting Stance/Champions Stance (One/Two Handed 20) - A significant reduction to stamina costs for power attacks when wielding one or two handed weapons, respectively. Less stamina use = more power attacks = lots of pain.
Atronach (Alteration 100) - Absorb 30% of the magicka of any spell cast at you. The only 100-level skill on the list. Atronach lets you absorb and regenerate magicka automatically every time a spell is cast at you. Alteration, if used at all, is fairly easy to level, and also provides a 30% magic resistance in the tree (via three ranks in the Magic Resistance perk at Alteration 30). The entire tree really bears noting, as you can easily outfit your character with everything except a shield just by using alteration spells prior to combat.
