As a huge fan and someone who owns almost all of his games I'd say avoid Kanban- that is due a redesign next year as he gets the publishing rights back and will be redesigning it ala Vinhos second edition.
As for where to start: The Gallerist, Co2 and Vinhos are probably the most straightforward of his designs. Lisboa is an amazing game but do not pick it up without having played it first. It's a huge monster of a game and requires a huge time investment not just to learn but to play. You likely won't get the game until at least your second play. You can optionally wait until Escape Plan comes out that should be landing next month and you can likely pre-order from one of the stores which are dealing with fulfilment. Which is exactly what I did for Lisboa and got my self a KS edition too.
