Hey Dan, If you're set on the EX250, good, don't let me dissuade you. If you really are thinking of riding the EX250 til next summer you might want to consider a few other bikes. One underappreciated bike is the Honda Hawk NT650, its a liquid cooled mid-displacement twin, great bike, light and nimble, unfortunately here in the Bay Area they have such a 'cult' following the prices are absurd.
Being Daniel Flory, if you are willing to go slightly exotic...
In most of the rest of the world, motorcycle licenses are "tiered" meaning you can't just hop on a CBR1000RR and go wad yourself. They force you to start on a smaller displacement bike. So 125, 250, and 400cc displacements are all big in Europe and Japan. Some 400's were imported into the US but they didn't sell well, now the good 400's are gray market imports only. For a californian thats a problem, as its tough to register non-california bikes, for someone who lives in America, its not so hard. So I'd say check your local classifieds for the Honda CB-1, Suzuki GSF400 (bandit), Kawasaki ZXR400, Honda CBR400, Yamaha FZR400, Suzuki GSXR400, and Honda vfr400. All are sport or sport-standard 400cc bikes. They'll be more expensive than an EX250, but probably more fun too.
atek3