To me, you're looking at the wrong two bikes. The KM is a good offroad SS bike, but the steamroller is definitely not a light, fun, zip around town kind of bike.

If you want something light and fun to zip around town, try the IRO Angus. It will be 650 shipped, but it has MUCH better components than the steamroller and is lighter with more agressive geometry. Also, the KILO TT from bikesdirect is a CHEAP option for a street FG.

I have no idea where you live or what kind of riding you will do, but I would venture to guess that you will spend more time on the street than off road. In that case, you should get a street FG bike (IRO, TT, Steamroller, there are tons of bikes in this category)

I would probably get that first, and then get the KM when you have money for a third bike.

just my 2 cents.

Also, you could get a cheapo kilo and also a mountain bike for like 700.