Well about the races:
Fyros live in the desert so not much seasonal stuff to see there, even no rain. It sometimes can be cloudy dough. This seems the most popular race amongst the players, at least it seems the most populated terretory.
Matis live in the forrest, they have thier seasons and it fairly popular amongst the players.
Tyker are the cute ones. You should pick this race if you like swimming, because a lot of thier terretory is water. There seem to be quite a few Tyker, but a lot of them seem to be wandering off do the Fyros desert and the Matis forrests. (maybe thats why Fyros & Matis terretory seem the most popular).
Zoraï live in a dense jungle, they have thier fair part of rain and snow. The jungle is dense and dampy with an occasional mob hiding in the bushes. I've found the Zoraï terretory the most easy to travel trough, but hard to leave. The Zoraï race is the least popular amongst the players and seems to be on the most isolated terretory.
Racial differences and impacts of fame will be important in the upcoming patches. Currently there won't be any difference in char development and abilities amongs the races. There is a difference regarding fame dough.
There are 2 powerful fractions on Athys, these are the ones who know the secrets of metal (karavan) and the secrets of the land (kami).
Matis and Tyker worship the karavan, Fyros and Zoraï like the kami more. The mask you see the Zoraï wear is sewed onto thier faces at birth, in respect of Jena, thier godess. Fyros are not such "believers", they don't build temples but they just like the kami a bit more.
History tells us that the Matis race are the most agressive ones. They've been in big epic battles with the Fyros on sevral occasions (and eventually lost every time

) and they have enslaved the Tyker untill the Fyros came for thier resque.
Zoraï live an isolated life, they tend to spend a lot more of thier time building temples, then fighting battles. Due the importance of thier religion, I don't see them working together with the Tyker or the Matis any time in the future.
Tyker supply the Fyros with water in return of protection against the Matis. So I see them working together with the Fyros race again, but there is a religion problem, ...
The Fyros are binded to the Zoraï by religion and to the Tyker due historic events, but Fyros, as the most fierce warriors, are vunerable and depend on the Tyker for thier water supply. Fyros are also responsible for the current situation on the planet. The released the great fire, wich destroyed a big part of the Matis terretory (the nort Matis desert) and thier miners started the big kittin war when they hit upon a cave and met the kittin for the first time. I don't know if the other races will hold the Fyros responable for this, it could turn against them sometime in the (near?) future.
Tyker are hard to judge. Because the worship the Karavan, I don't see them working together with Zoraï much. They were enslaved by the Matis, but religion binds them. The karavan have proven to be strong enough to unite the Matis and Tyker against the Kami races (Zoraï and Fyros) during last 2 big events on all 4 servers. I don't know if the Tyker will settle thier differences with the Matis and bring the Fyros race in trouble by cutting thier water supply, or will they remain loyal and keep depending on the Fyros??? If the Tyker grow strong enough to stand up against the Matis or even become thier allies it isn't looking good for the Fyros.
So, thats some background info about the races, jonhop, I hope it will help you make the choice that fits you. You could read up some more on the ryzom website about the history of the different races and fractions.
Currently, it doesn't matter much wich race you pick, but it sure will matter if the story develops more in the coming months ..