I was originally going to do this as a one article but decided that it was too long for even me to read so I have split it up into two sections. These represent my favourite minis in no particular order.
This is where a lot of my mini money has been spent in the last year or so. There have a broad range of figure genres. I have posted about parts of the Modern range already as they do some nice modern US troops. They do a good range of modern nationalist and some, like the Chinese, that you would be hard pressed to find anywhere else. They have a nice range of insurgents and paramilitary types. They are probably have the biggest range of modern zombies out there and a nice range of WWW2 zombies in 15mm. My paint queue currently has some of the Sahadeen SF infantry. A nice low tech-ish force that kind of evoke the Fremen from Dune to my mind. The 15mm Gangs, Gunmen, Hostages and More do some nice civilians and post apocalyptic minis. They also have several nice range of police types.
Khurasan have some of the nicest figures on the market at the moment in my humble opinion. The range of genres the cover is also quite impressive. Like many others, some of the ranges have been inspired by film and TV which allows you fulfil some gaming fantasies. Their SF ranges tend to be just about the right sizes and have enough figures to make a decent force out of. I have mentioned their Alien/Aliens figures before which I like. Again HALO fans will find something in their ranges for them. Their Lhurgg make nice tribal aliens with high tech weapons. The felids are a great (and growing) range of feline aliens which have brought a lot of attention to them as a manufacturer. This is just a taste of what they offer in the SF line. They also have a sizeable fantasy range with some nice lizardmen and the Getinmahbeli HOTT army. They also have a largish post apocalyptic range which is inspired by the Fallout series of games and have moved onto zombies and survivors recently. As a big fan of Fallout, I have to say I like them a lot. They also do a lot of pulp figures that would not look out of place in a Doug McClure film. They also do a sizeable range of historical figures in more eras and nationalities than I care to mention.
I have been a GZG customer from twenty years and have nothing but nice things to say about them and they have a big range of minis. They do listen to their customers and produce what people want. Mainly an SF manufacturer but they do a interesting range of other figures. I think they have the biggest range of SF vehicles and several of them have compatible looks. They have some nice buildings in a couple of styles which look nice on the table. They are currently well known for their 15mm work but have extensive range of 25mm, 6mm and SF star fleets. One of their biggest selling points for me is that they supplement their military ranges with plenty of civilian types including some fireflyesque miniatures. If you were interested in firefly their Free Cal Tex figures look a lot like Alliance (and the film version of starship troopers for that matter). They have a fantastic turn around time (most of the time just not when they have an offer on or when Salute is coming up). They are good attenders at UK shows and Jon can usually be engaged in conversation about what his plans are. They know their market and excellent customer service.
This is a smaller manufacturers out there. That said it is one of the reasons I was able to make the switch to 15mm. They do not have a huge range but what they have is very nice with lots of character. They tend to be useful for contemporary games. They have some nice secret agent types which fit in well with the minis from Rebel and some special forces types that would work well against Khurasan's vacation aliens. Much of what they do would work well with post apocalyptic games and their robots evoke Fallout 3 quite nicely. Although they don't do zombies they do some nice zombie hunters and some of the body bag figures would be nice as zombies. The Scene also do a lot of nice scenery and hard to source items. What I like about The Scene is that sell figures individually so you can get exactly what you want and don't end up a pile of useless lead that you can't even get rid of on eBay.
If you are looking for 15mm fantasy figures look no further than Splintered Light. The have a vast range of races and even a few you have never heard of. When I was considering doing a Narnia army, this was the place to go. There seems to be some sort of obsession with fantasy mice (maybe something to do with Mouseguard) and SL have a nice range of fantasy armed mice and other woodland creatures. They have some nice Pulp figures (currently only just represented by a few manufacturers) and a range of SF ships crew which would work well for firefly/Serenity. They also carry a limited range of ancient medieval figures.
I'll finish this off shortly.