Greeting guests @ cocktail hour or during dinner????

We greeted out guests during cocktail hour and during dinner. So it's really up to you.

Are you having dinner also? We're not doing a receiving line either. We're going to use cocktail hour to take pictures, make our entrance, start the buffet, then eat our food quickly and do table visits while everyone else is eating. I don't think it's bad to greet while they're eating - it's the best way to make sure you get around to everyone, since they'll be seated. And it makes it easier to just stop by and say hi without getting caught up in long conversations.

We also did both. It worked really well for us.

@Rebecca: Yes, we are having a served dinner.

If you want to make a grand entrance I would suggest getting people at the dinner. No one will be put out and like @Rebecca said its the perfect way to keep things short. Most weddings I've been to have done this

We had the dreaded "gap." After my first wedding, when I didn't have one, I had some insight. As long as you don't keep people waiting for more than an hour, it's fine. Not only did no one complain, people were late to the cocktail hour. Anyway, we didn't do a reception line, and we ended up seeing some of our guests at the cocktail hour, and others, we went table to table at the reception.

We aren't doing a cocktail hour so our plan is to speak to guests at their tables during the reception.

We are doing exactly what you described!