How essential is it to play Half Life 1 before playing Half Life 2?

It's not REALLY necessary.

Not really that important, but I would suggest playing Black Mesa.

If your in it for the story, Then Half Life 1 shows you how it all started, and may make Half Life 2 a little less confusing. If your not a fan of the graphics (It is a pretty old game), Try playing Black Mesa, Its a remake of Half Life 1 using the Source Engine, and it try's to be as close to the original as possible (With Minor changes here and there).

It's not necessary but the background info will surely help, here's a speedrun of HL1 in 36 min Clicky

Necessery for better story understanding... also... THEY ARE BOTH EXCELLENT GAMES

But if you want to skip the old graphics not really a big problem

HL1 spoiler-free recap for HL2: you are the silent protagonist Gordon Freeman, a scientist newly arrived to Black Mesa, a secret research facility. You don a hazard suit as you prepare to conduct an experiment that you're late for. Things go wrong, aliens arrive, and you "clean up" as much of the mess as you can. Later, the military also decides it's probably a good idea for them to step in. Some of the first aliens you encounter are affectionately called "headcrabs" because they jump at your face, latch onto your skull, and slowly turn you into a mind-controlled alien zombie (actually, in-game, they just kill you, but that's what they do to NPCs). Also, there's a mysterious guy in a government suit who talks funny. In the end, you win... or lose... or... well, it's not very clear.
Cut to HL2.

[edit] Also, the facility's security guards are nice. All of them are named Barney. (Technically, none of them are, the name is a developer joke... but a retcon for the Blue Shift expansion and HL2 means at least one of them was.) [/edit]

Not very. I played HL2 first and wanted to play the first one to see how Gordon Freeman ended up in this situation. When I played HL1, I got confused.

Half Life 1 is one of my favorite games of all time, but to those unaccustomed, the graphics would dull the experience, though its not really necessary - just so you know (very slightly more) about who you are - and for a joke in episode 2, other than that its fine without it.

as others said Black Mesa Source is your best bet.

its not essential at all. the situation, the characters, they'll all be introduced and explained in hl2, so you dont really need to play hl1.

I dunno but I think you really should play Half-Life 1 because it's a great game. Also Opposing Force and Blue Shift:p Also Black Mesa: Source is pretty crap, and it's missing stuff from the end of Half-life.

dont know bout anybody else but i generally like to play a series from the start.

it is a good idea, but not necessary

If you don't get Barney's line near the start of HL2 then you don't deserve to play the game...

get half life source http://store.steampowered.com/app/280/ if you only want to play the game, or get normal one if you want to play on mods too.

Half-Life (original version)

• +more "authentic"
• +many mods are available
• +autosaves at loading screens
• -technical issues from it being an old game

Half-Life: Source

• +minor Improvements made to the physics, lighting and water effects
• +runs better on modern computers
• +you can begin a new game from any chapter
• -autosave feature was removed
• -no mods

They do keep referencing to events from HL1 and you won't know why you end up at the start, but you could play it just fine without it.

you can play the remake called Black Mesa for free! here

It's totally legal and it's coming to steam too (greenlight)

I'm waiting for Black Mesa to release on Steam in September, before starting HL2

Play HL not HL2. I can't even imagine how overrated HL2 is...

I'm usually a stickler for playing games in order, but I played HL2 before I played HL1 because it was what was available to me. Even though I was completely confused on the backstory and stuff, it probably made me love the series even more because I really wanted to go back and figure it all out. It was almost like how a movie has flashbacks or tells a story in reverse. It can make for better story-telling.

Play them in the order you think you should. Both ways have their benefits.

Downloaded Black Mesa - tomorrow I shall begin:D
Thanks guys:-)

HL1 is better than its sequel.

Spoiler: Gordon saves(destroys) the world(boxes) with a crowbar; candidate for god. Other candidates: Morgan Freeman, That rock, A bird I found, and my cat.

Play the goddamn original game. It's a must play, seriously, what are you doing here not having played it? And stop masturbating to graphic, never did anyone any good. Cheers.

summary of the conversation so far:
Half-Life 1 > Half-Life: Source > Black Mesa: Source

In other words, Black Mesa sucks horribly while Half-Life 1 is a great game