[quote name='Hydro2Oxide']Hey, I'm sure this question gets asked a lot but some minor searching didn't find me any good answers.
Just started playing, I'm wondering what champs are must-haves from the get go. I don't want to waste my points on weak heroes, so any guidance would be appreciated.[/QUOTE]
The champs you need to know how to play stem from the current metagame makeup which is a ranged dps, an ap nuker, a tank, a support, and a jungler/ganker/off-tank, so you should pick at least one hero for each role, usually you'll want one with either very high mobility or a ton of cc/stuns:
Ranged DPS: Ashe
Ashe is Valkyrie on crack with Drow Ranger's slow. Think valk's stun, only it doesn't hit minions and its range is the entire

ing map. A cone slow/damage attack that scales with your attack damage, a passive slow, a skill that increases the money you get and can be shot almost anywhere on the map to reveal the area (a free temporary ward basically), and of course her ult. That

ing ult. Infinite range, 1 minute cooldown, longest stun in the game, its like 4 times the size as valk's spear, it doesn't hit minions so you can shoot through creep waves, it does great damage, it slows the enemies in addition to stunning them, and oh yea, the damage and slow is AoE.
AP Nuker/Carry: Annie, Ryze
Annie- Hellbringer's Ult with solid nuking power on top of it. Also a mechanic that allows any of her spells to stun not just her ult. She is very bursty.
Ryze- A sustained damage champ. Your role with him isn't to burst, but to keep hitting the enemy. He's a caster DPS that scales off mana meaning you can build survivability items that grant you mana and be very sturdy in addition to doing ridiculous damage. Has a point and click snare, a skill that lowers enemy magic resist, a single target spamable nuke, and his ult makes all his spells become AoE.
Tanks (tank/disable)- Shen, Rammus, Amumu
Shen- Dash taunt like legionare only in a straight line. Doubles as a chase/escape mechanism since you can dash through walls and shit. An ult that allows you to target any allied champ, teleport to them and give both of you a damage shield.
Rammus- Free armor/mr, free blademail, a movespeed boost that slows down enemies and interupts channeling, a single target taunt that lasts twice as long as shen's multitarget one. Also, he has Magmus' ult except it lasts longer and does less damage per tick.
Amumu: Keeper of the Forest's Ult+a % hp based hp drain aura like soulreaper+a spamable aoe damage thing like soulreaper that has passive damage reduce+a stun/initiation move like pharoh's ult only slower and less range.
A champ who can jungle and gank and be useful in a lane: Too many of these to list.
This is a utility spot on your team so you'll just have to know what heroes your team has picked and fill in the gap. Early on Nunu will work for this. He can jungle easily, he's got a good slow/nuke like glacius, blacksmith's buff that increases move/attack speed, a self heal, and his ult (which is also similar to glacius' except it does 0 damage until the channeling is completed) while pretty shitty since its got a long ass channeling time means that you'll be targeted with all their stuns and shit making him a pretty good tank as well as far as an offtank goes. He also has one of the highest if not the highest base hp in the game.
A support hero: Janna, Taric, Morgana
Janna- Damage shield that increases damage, a slow, a knockup which is like a stun that nothing can be done about, an ult that knocks all enemies away and heals your team. Her passive is a global move speed increase for your team.
Taric- A point and click stun, a passive armor buff aura that you can trigger to do damage and lower the enemy's armor, a heal that heals yourself and the target, an aura ult that heals and increases your team's damage.
Morgana- A shield that functions as a Shrunken Head that you can put on anyone AND you can still cast beneficial stuff on the person (has a damage limit absorb however), a skillshot snare, a "puddle" spell that does damage and lowers enemy's magic armor, and an ult that does damage in an aoe area to start which slows the enemy and if you stay near them till the ult ends it does another burst of damage and stuns everyone around you.
There are of course other heroes that can work just as well in their categories, but I consider these ones to be "core" and fit pretty well in any team.