50/50 tire suggestions?

[Why Z?]

Hey, so I just bought my FSR 450 and I love it!

But thinking for now, since I haven't totally figured out where the trails are, I will probably be doing more road riding than the stock enduro tires are made for.

Basically, main concern is the tires on bike are BRAND NEW and I don't want to wreck them road riding.

What I am looking for is:

-50/50 Dirt/Street tire (or close to that)
-Decent performance in dirt, and a variety of offroad conditions.
-Durability on street (so I am not replacing all the time)
-DOT a plus, but not necessary. (Nobody really cares in MN)

Please note: it is not so much "better performance" on the street that I am looking for, but just the tire not getting "worn out" as fast. I don't want to destroy the brand new beautiful enduro tires on the street until I have some place to use them!!!

Any suggestions on something that is good for what I am looking for, and preferably cost-effective (doesn't haev to be CHEAP CHEAP CHEAP)

would be great!

OH yes, and please let me konw what size(s) would be best!