ORIGINAL: US3R!!!11one

It depends what you want to do.
1. Drag & street racing - H22a. (I call it my "Honda Big-Block" =D ) Cant beat the torque and heavy weight in the front helps the FWD launch a small bit. Despite what people may say, there is large aftermarket support, and the engine is cheap and cheap to mod. Due to the size it can be a pain in the *** to get in and work on, but to me its worth it. Be prepared to have your handling screwed though. It requires a near full rebuild to turbo, but in all honesty, if your going to turbo a car you would want to do this anyway. The engine can run a 100 shot if nitrous reliably with small fuel mods & a sparkplug change. Depending what model civic you have, you might not be able to consider supercharging, like with me, I would have to cut through the strut tower in my car.
2. Auto-x and if your considering taking your car over 600hp - B18. As already stated, this motor is nice. Lightweight, strong internals, plenty of aftermarket, but sorta expensive. A good choice for an auto-x'er that wants a little power, or someone who wants to turbo a motor right out of the box without much work. Also the better motor for reliablity due to the chamber design if you want to take the car over 600-700 hp.