Christoph, boots would be great for denim and chinos. Chelseas would be killer, but be sure to consider wingtips, Jodhpurs and balmorals. The bal boots might be a bit dressier, but would still look great in a brown leather or suede (or combo of those).
Epaulet apparently just put in orders for a burgundy shell wingtip boot, which I think will be great for casual wear. If that's up your alley and you're not in a rush, you could wait ~2 months for those to go on sale.