I had the same pondering when I was about to buy my bike
I was buying new so the monetary difference was only $1600, that's a Husky no brainer in my book, that amount will not get the DRZ one third of the way to where the Husky is Stock plus I was daydreaming/drooling over the 610sm looks... however lack of interesting terrain and coming back to riding after a 13 bikeless years made me chose to shelve the yearnings and go with the DRZsm, my boss thought otherwise and gave me a present; 08 610sm (so just work hard....it'll work itself out.....
)
My neighbor has a 06 DRZsm with a Yoshimura pipe, jetted right, my take on it is this; the DRZ is skinnier between the legs, it's power feels more "electric" compered to the 610 "explosiveness" (mind you, you could ride the 610 in an "electric" manner, just short shift it.... )
The DRZ is good enough but not nearly as good.... (as the 610)
The DRZ's clutch pull is outstanding!!! you can use your pinkie to shift gears, on the 610 you need two fingers and you better mean it...
you'll spend some good money
trying to bring the DRZ to the mind blowing level of
outright dirty, nasty sexiness of the stock 610sm
My neighbor take on my (stock)610sm was;
Damn this bike is SICK!!! (he was amazed at how much "more" the bike is, loved the extra power and the [stock] pipe bark...)
My opinion? you really need to look at what you got to work with, $2800 is a nice chunk to help the DRZ come two thirds to the 610
You'll be happy with the DRZ if you chose it....
However don't go test riding the 610
after you buy a DRZ...(it'll hurt)
Good luck
(probably oughta marge his two threads, both have good stuff regarding the same subject...?)