have you ever found you can't afford some miniatures for your games? especially more modern based ones?
try using lego men.. seriously, and check out this website BrickArms. They made guns for lego men based on modern weapons, plus they have a couple from the aliens movie.
With Lego making mech type sets (exo-force) you can use your lego for future setting campaigns too! I believe the website Brick Shelf that has a lot of people who've put up their designs that you might find useful to use as minis.. true, scaling will be difficult, but still.. fully customizible and CHEAPER than other mini lines.
