Julie - I understand your enthusiasm, but lets' get down to earth a bit.
$30K spend typically gets you 30K miles. Maybe a 10K miles signup bonus.
A "standard" domestic round trip is usually 25K - off-season (some airlines) would be 20K. So, you mught have enough for two people to make a r/t once a year.
However, a growing dirty little secret of the airline/FF game is that these "standard" awards are getting harder to get (tightening up availability, reduced capacity since 9/11, etc.). With some airlines, you can get a "rule-buster" ticket, at twice the standard rate.
Internationlly, 50K miles is the normal threshold for a coach ticket. Business class 80K-100K, First 100K-150K. This is typically US-Europe. For Asia. S Pac, etc. expect to pay more.
So ... yes, it can be done. I do it, most of the others on this board do it. But it's not like paying for your newspaper with a credit card and then flying to Tahiti every year!
My advice - listen to the folks who have already replied. Start earning some miles. Read the other forums to get a feel for how the programs work and which one(s) would be right for you. Then you go, girl!