working for just a year and then heading to b-school is actually
not that common. If you look at the average # of years b-school applicants are, they typically have worked 4 to 5 years, granted Harvard and Stanford are more leniant on age as we see a trend in accepting younger students. But for most of the other ones, such as Booth, CBS, Tuck, Darden, Ross, MIT, Yale, etc., average number of work years are all 4 or 5. Again, does that mean no one gets accepted with just 1 year of work? Not necessarily. But you'll be facing an uphill battle and an extremely hard time to answer the common MBA question - why now, after just a year of work experience?
Also, I think you misread the comment from other posters. GMAT is not accepted anywhere else other than b-school. GRE, however, is now accepted at some b-schools. GRE is going to change by August, 2011, and the verbal section (synonym and acronym will be voided) and GMAT is due to change some time in 2012.
I just want to make sure that you make an informed decision on what you want to do with your life. If you want to take the GMAT right now, feel free to do so if you think you're ready. Just be aware of the 5-year-deadline (which by that time, you'll be taking a different GMAT some time in 2012)