Yes, the community patches work fine with the Steam version. This is an amazing game, but you really need to install the unofficial patch before playing!
Coming to this thread without having played through is just asking to get spoiled, spoiler tags aren't a waterproof system, people have different ideas what should be between tags or not.
I think a week ago or something there was a small article in PCgamer with a concept art image of Episode 3, stating development has started, so they're just starting. I'm afraid waiting for Ep3 will take a long time.
I agree with z3rb, but if you don't like HL2, you maybe won't like Ep1 either, because it stays very close to HL2 with gameplay and environments. Ep2 adds a lot of new stuff ans is really awesome.
You should try them both, but don't skip Ep1, otherwise you miss a lot of story.
I just moved all the cars off the bridge, then it will balance all the way to the other side, so you can make a nice jummp with the car.
You don't have to balance it perfectly.