I posted this on a guy's post that was asking pretty much the same thing, only difference is you may want to consider a TW200 as it has smaller wider tires. Smaller tires inspire confidence, as do wider tires, especially in rocky situations. Also, the xt225 is a must consider for weight reasons alone. Be sure to get the weight for everything you consider and consider it.
repost:
I am here to settle this - DO NOT get a heavy bike, KLR 650 is 400+ pounds, DRZ is almost 300lbs, Yamaha WR250 (great bike but still 300lbs) ie. might as well get a KTM 690, it's 300 lbs. Scratch all those, get the lightest damn bike you can find which would be the Yamaha XT225, it is like 230lbs, great bike great reputation, super cheap, you can get like '04s for $1500. Dont even get the new XT250, why, its 300lbs.
Think of it like this, go get the XT225 and strap 75lbs of dumbells on it if you want a heavy bike. I hear DRZs handle about as bad as XR400s off road. If you want something with the power of the 400cc motors, get a KTM 250 (4-stroke), same power, less weight, handling between the two will be insanely different - ktms will make you a better rider - set up different, way more suspension (which saves ***, trust me).
I would get the KTM 250 if you can find a good used one at good price, the XT225 is a great bike also and cheap and already tagged. I personally have a 1987 Yamaha TT225 which is the exact bike sans lights and tag, but the TT-R225s are not the same as the XT225, the TT-R is like 300lbs too. I keep the TT225 around for people to learn on, it's 222 pounds, little lighter than the XT. I've personally rode a Yamaha WR250, nice bike, fuel injection is nice esp if in the mountains, bike seems pretty street bike though, weak suspension, no bottom end power and 300 lbs still which mean an XT225 plus 60 lbs of camping gear.
KTM 250 XCF-W - 101.6 kg (223.98 lbs) (the four-stroke one) approx. 35 HP
XT225 - 238 lbs
DR-Z 400S- 291.0 pounds, Measured horsepower: 32.5 bhp @ 7850 rpm
klr 650 - 387.0 pounds
KTM 690 Enduro - 305.3 pounds
WR250R - 295.0 pounds
http://www.xt225.com/
Finally, you'll want to consider maintenance. If you want zero maintenance, get the XT225, The KTM 250 is going to require more frequent oil changes and have to keep valves adjusted. Just depends if you plan to ride off road or on road more. Dirt/Street%: 90/10% get the KTM 250 - 70/30 get the XT225 - 50/50 DR-Z or KTM 690 - 10/90 KLR650 DR650 GS650 KTM690 KTM640. The thing is, if you ride a lot of road you'll want more motor (KTM640 or 690).