Thanks for the replys.
I think D20 modern sounds good, but then again im probably just saying that because ive done DnD, but still.
As for the campain, first I'll explain a bit of why.
Its kind of an old dream I had from my early school years. Me and a friend, Tom, used to play out little adventures in our imagination (surely looking quite weird as we did, but anyway) based in this world we had made. Like many do, I said I would turn it into a computer game some day. half way through school Tom and I got split up (dif school, new homes etc) and didnt see each other untill about two years back. Of couse the days of running around the field and dodgeing asteroids (annoyed football players

) were over, but I continued to develop the world in my head. All the time I saw things that would give me an idea and, Bang! That funny chair is now a space station. Over the years Id say my little universe has become quite developed (and is still going), with new ideas and also countless cliches worked in and then out again later when I realised how stupid they seemed. But all this was happening without Tom, so when we met up again it just wasnt his anymore, he'd mostly forgoten it and not done the same as me. I realised a great way to relive the old game would be as PnP RPG, I could let Tom explore my world that way, with only the most mundane knowledge of it, just as his character would. Also it would be a chance to go into developing the setting in more detail and a more personal scale than I had before.
The setting its self is obviously a big thing to explain, but in brief its a far future world, Sci-fi i guess, Im just reluctant to put that label on it. Far reaching and fast space travel is possible, and quite widely availible. futuristic weapon are all over, although the good old bullet can still be put to use. There are multiple power centres and races, Includeing a looming threat or two. Ive developed a colection of planets. The world doesn't have
super high tech, for example no teleportation, grav lift type things, energy bridges, uber matter manipulation, etc; but cloaking, shields, artifical gravity, hover craft exist (all with certain limits), and there is always new things as yet not understood. I kept a certain amount of grittyness to the world, but not too much. No magic or psy etc.
That should do it. My idea so far is for the player to start on a outer planet, with a distance between the centres of the main societys. But provided he can find a way, he can get there, do that, and get the t-shirt.