One nice perk about government work is that there's zero haggling over salary—your income will be laid out on a nice, snazzy scale that you'll know going into the job.
Right out of college, a candidate could apply for a GS-5 position, which pays roughly $35k. A master's degree or two years of experience with a bachelor's degree will take you to a GS-9 position that pays about $50k. This scale goes up to a GS-15, where scientists tend to bring home around $120k. But don't forget the federal government's benefits package, which can stack up quite nicely to those in the private sector. There's health insurance, vacation time, federal holidays (usually one day a month, like Martin Luther King Jr. Day), 401k plans.
But while the pay scale is right there for the ogling, there still can be a few potholes along the way. Usually the pay follows the rate of inflation, but times of economic trouble and political pressure can lead to federal pay freezes. That's exactly the case now at the EPA and other governmental agencies—no matter how good your work, you're going to have to bide your time until Uncle Sam says you can get another raise.
The pay may not blow your socks off, but the federal government is known for their job stability. Once you are in, you're in—assuming you don’t do something nuts like stick a goat in your boss' office. The government is not prone to massive lay-offs, a definite perk in our tough economic times.