I have an xr650l. I wiegh like 185, 6foot 1inch tall.
Heres what I have found, Rented DR 350's in costa rica with friends. I find the DR's are less quality and break easier but they are light and fun and we were able to go anywhere we wanted including down the beach hammered one night
Pro's - light, fun, cheap to buy
cons- not as hardy, to small for highways
My xr650l is great on the highway under 75mph. If you are driving on the highway alot then get one. any 1996 or above is ok so should be able to find one under 2500 bucks. The thing is useless on the trails unless you want to go on dirt roads. it weighs in somewhere around 550 lbs and is hard to throw around at my wieght. Theres a good chance I will hurt myself this year on it lol. I have had it fallen over alot and its a bitch to pick up alone on a steep hill. I had to drag it for a while to a gully to get it back up on a steep dirt hill once. But no broken parts to this day!!
pros - good on highways, solid hardy bike.
cons - more expensive, heavy for dirt, hard to throw around.
I think since you are in colorado you should get a bike that is made for dirt and convert it for street. What I have found about enduro's is that you sacrefice things. Its not great on the road and its not great on the dirt, it just allows you to do a little of both.
If your on the highway 80% of the time then xr650l or dr 450+ or kawasaki 650, that hunter green one.
If your taking roads not highway then I say dr 350 or wr450 -400 would be good, and still fun in the dirt.
If I had it to do again I would get a CR by honda and convert it to street so when I get in the dirt I can rip. I just feel the xr650l is a dam tank and the dr350 is to small and lacks balls. those are the two I am most familiar with. I have a friend with the wr 450 and he swears by it, but he doesnt take it on I-70 like I do with my xr.
Good luck and just remember getting one is the first step. Its impossible to not have fun on it. So I would say buy the best deal you can find and worry about upgrading later on.
The cons of the wr bikes is that they are not that old so prices are still kinda high.
Bottom line if I planned 50% dirt 50% street no interstates I would find a an xr400 because they are the cream of the crop.
or a cheaper wr400-450
Next choice would be
DRZ 400 (street legal) http://www.bikepics.com/pics/pics/su...pics-38188.jpg
But I find the DR's are to small for my likings and hieght.
Good luck mate