I'd need to ride them for sure, but the DS1 interests me, with its steel fork vs. the aluminum fork on the DS2 and above. It should offer better ride compliance. I'd consider that model and then upgrading to hydraulic brakes.
I don't like how the fork appears to be matte black on all frame colors. I think that's a limitation of suspension forks -- they don't look well integrated into the bike. Trek paints its Verve forks the frame color and I think it should do the same with its DS forks.