I've owned 5 Vstroms. 4 DL650's and 1 DL1000.
My first DL650 was an 04 and then my next DL650 was an 07, and since then I've owned an 08 & 09 DL650. The 04-06 DL650's are great and nothing to shy away from, but going from an single spark to dual spark, I did notice a bit smoothness and a bit better fuel mileage. Some people feel the earlier ones were a bit stronger power wise because they had less emissions stuff on them. Basically, if you buy an 04-06 vs an 07-11 you won't notice any difference unless you had a chance to ride them back to back to pick up on the small changes. The 07+ do tend to get better mileage, but that's not to say the earlier ones get horrible mileage. I think where the 07+ get better mileage is on the back roads running 55-65mph. Once you get over 70-80mph, both models of the 650 start sucking down the fuel.
Some people don't like that there is less serviceable parts on the 07+ and takes more special tools for some simple things like a TBS sync and such.
Find one that works for you and just go with it.
Mine: KTM 650 ADV Katuki, 09 DL650, 08 Husky TE610, 08 WR250R
Hers: 07 Ninja 650R, 13 CRF250L
Last edited by BlueLghtning; 03-12-2012 at 02:36 PM.