I don't think waiting until the altar (to kiss!) is necessarily the answer. I don't want my first really, clumsy, inexperienced kiss to be in front of a multitude of family and friends! Besides, there's a huge difference between kissing and pashing. The former would be acceptable, the latter could easily lead to more... In the end, you need to make boundaries, be informed by God's Word and talk to God about everything.
I don't think I'd go anything beyond hugging, holding hands and quick kisses. And the kissing would only be in the engagement phase, when the relationship is incredibly serious.
I don't want to be one of those Christians who doesn't save themselves for marriage (see too much of that in the Church as is) but I also think the extreme opposite is not necessarily ideal either. In the end, it's between you and God and the person you love. And in all things, respecting the Temple you've been given.