It's not a simple question to answer, because the rules are likely to vary depending on where you are in the world. In the UK and most of Europe, for example, you are legally only allowed to fit lamps that match the bulb type that the light fitting was approved for. This means that - in the case of your car's main/high beam headlights - you are only allowed to fit halogen bulbs.
Having said that, I understand that in some European countries it may be possible to get LED replacement lamps that are legal to use in halogen fittings - though this is not so in the UK. It may be worth investigating that option. Osram is one of the manufacturers, I believe.
Otherwise you should consider one of the higher-output halogens that are within your country's legal power limits. Both Osram and Philips have a large range of these.