Well, excepting carbon rims, and the high profile American classic alum. rims, most high(er) profile rims (30mm) are going to be in that 500+ gram range. Even the CXP's are up there. So, no easy route to ride. There is a bit of a benefit to the heavier rims, in that they do hold their speed pretty well. Slower to get up to speed, but once there, you tend to work less to keep it there.

Some of the IRD rims are getting good reviews and they are a "bit" less weight.