I've looked around but there doesn't seem to be anywhere near the amount of information they used to be, it seems to be very spread out. Even the Jane's books seem pretty crap nowadays compared to the one I got about 10 years ago, they have an online database but at £1,800 per section (i.e. aircraft, artillery/armour, ships) well, no thanks

Edit: Wikipedia seems to have some info but still lacks many images and 3-view diagrams, at least it has some inventories of various armed forces though.