My height is 5ft 7inches what size of bike fits for me i am 160lbs.?

At 5'7" tall you should be able to handle the DRZ just fine. You can always do things to lower it like slide the forks up in the tripleclamps and drop your subframe if you need to. I am 5'5" tall and ride a YZ 250 which has a 39" seat height with no problems. It may take a week or so to get used to it but I'm pretty sure that you will be happy with a DRZ-400

http://www.koubalink.com/drzinstall.html

A 400? Well, it doesn't necessarily matter how high the seat is unless u get into 1000's. Thats when you can see a bigger difference on how high you sit on you bike. What you need to be more concerned with is how many cc's you can handle. Some guys go with 250's to start out, but you will get used to a small bike like that. If yu want a bike that isnt TOO big but has good power and is a bike you will keep do to it being plenty big. I would go with a Ninja zx-6r, yamaha r6 or a Honda CBR 600rr that what I would go with. My first bike that i owned/rode was a 2006 CBR 1000RR. and im only 6ft 185 but thats a perfect size for a bike that big. But it all comes down to how comfortable you are with the bike. The bike will feel intimidating at first but don't worry at first because you will get used to it within a few weeks of riding it.

Im 5'5" and a half and 140 pounds. I ride a drz 250 and it was a little too tall for me. I got a lowering kit to put on it and it fits me perfectly. you probably could be able to ride it easily without a lowering kit but also if you want something that will last you a long time a 400s is perfect. Also there are a lot of them for sale on ebay and craigslist.