The Worlds of Aldebaran series is excellent, I picked up the latest book - Antares, episode one - the other week and am now waiting impatiently for Cinebook to hurry up and translate the next one. The art is fantastic and the alien creatures are both truly alien and at the same same totally believable. Leo has done a cracking job of creating alien environments.
I've also got the four volumes of Orbital which is a good read, just hope there's more to come otherwise the series has a seriously downer ending and leaves more questions unanswered than it does answered.
I first started reading them when the local Forbidden Planet got a rather fancy carousel filled with a load of their titles at rather attractive prices (£6-8 a book), and I planned to work through a few series buying one or two books a month. Sadly the lazy buggers at FP haven't bothered to re-order any stock and the carousel is now slowly filling up with various Marvel and DC titles

Fortunately Amazon seems to stock most of the range and if all else fails I'm thinking of buying straight from the Cinebook website.
Anyone got any suggestions of what I should go for next, XIII looks interesting as does the Chimpanzee Complex.