Can you guys all share your wisdom on differences between seed/pre-A/Series A rounds?

YC has done an amazing thing by standardizing first-round terms. But what is the next level? When people get out of YC what sort of funding situations are they facing? What do investors expect to see and what kind of equity do people give up?

I'm asking because people talk about companies that still take "seed" rounds but the term has become so amorphous it is impossible to know what it means as someone outside the Valley. But if you can get funding on better terms it seems a waste to give away 7 percent of the business for 120k to start.