I dunno know. Without a street bike, you (if your like me) might start missing the street. With a duel sport, it sure is nice to hooligan ride around town, and like you say, be able to ride to the local trails and such.
Might want to check out the prices on a DR350s (street model), 1990-1999. The later year DR's (maybe 1996 and up) had the same suspension as the off-road models, and as such, are a little more desirable. Very nice ones can be had easily for within your price range. Plus they are absolutely bullit proof.
Remember, making a mx'er street legal could set ya back a fair amount of change.