BIT OF A LATE REPLY TO THIS ONE, BUT....
I just sold an old DR600 (1986) which had 50,000 kms... was a good old bike, but getting a bit 'long in the tooth'..

Leaked oil here & there, but pretty tough, gear box was still OK, kick started OK, economical and basic motor.
So, I have just got hold of a TTR600RE (2004) with only 6,000 kms. Its about the same weight as the DR, but as so much newer, is nice & smooth (ride & power) and as already debated, a bit taller.
Minus points are lack of accessory choice & manuals are like hens teeth
Only just got the bike so don't have an in depth view yet, but so far - so good. But as its only a revision of the old XT, nice & simple mechanically. Another plus

coz they ain't so popular as DR's, is they are a fair bit cheaper... got mine for £1900 with new a Mot & Skorpion Pirelli's