I think Alternity would also work very well for what you want to do.
The biggest downside to it is that it is OOP. It is available on eBay and at some gaming stores (nobleknightgames.com used to carry some. There are also some things in PDF format at svgames) and usually for reasonable prices, if you are patient. In fact, with the increase in prices for printed material, Alternity is priced no more expensive than today's games and can sometimes be picked up for less.
The only other downside to it is that it is a new system to learn and it will take time to learn all of the nuances, which it does have.
Having said that, it is a GREAT game! It has your laser guns, rocket launchers and other SciFi elements. It has great options like mutations, psionics and cyborgs built into the system as well. It does allow for a chance at death in combat while still being heroic. It also has penalties for damage that are easy to track and will put a character down but not kill them.
As it is OOP, there are a finite number of books that can be picked up for it, which is both good and bad. There are 4 books that expand on the basic ideas in the PH and the GMG. One hasn't gotten good reviews but it is still useful in my opinion. The others are good and have a lot of good ideas.
There are two settings that can be found for it. Star*Drive is the futuristic setting with space ships and aliens. It did feature a good meta plot that can be used or not in its limited run of books. (Again, I have seen all of the books on eBay and sometimes elsewhere.) There are probably a dozen books or so and all are quite good. I have used this and do like what they set up for the setting. (If I were to do it again, with my players permission, I would probably do something more like a Firefly type game and this would handle it easily.)
Dark*Matter is a setting of conspiracies. (If you read d20 Modern, many of the elements from D*M have been used in some of the books.) It is a very good book, detailing conspiracies. The setting allows from some FX (magic) but nothing that can get very powerful. It would be possible to run X-Files to Buffy using this. btw, many people think that d20 Modern "watered" down a lot of the things from D*M. There were maybe a half dozen books for D*M, if that many. I have also used this and really like it for modern gaming! I think it does a great job!
(I am biased of course but I really like Alternity. I am currently using it for a Fantasy game and it is working out very well! I couldn't be more happy with how well the rule set is working for my games!)
Finally, there is still good community support for it at alternity.net and tequilastarrise.net, which is specific for S*D. There is a fan ezine, including a lot of back issues, a character generator and lots of other downloads to support the game.
I have been really happy in using Alternity as my role playing game of choice. I hope this has interested you enough so that you will check it out!
I hope you find something that makes you happy! Have a good one! Take care!
edg
btw, there are several reviews for Alternity at rpg.net if you want to read more about it. Those are the only ones I know of right now.