One thing I've realized about the miniatures gaming hobby is that you need a lot of terrain unless you want to fight in the desert / plains / snow all the time. Accumulating all of this terrain is practically another hobby unto itself, with a different set of skills required if you're the DIY type of person. For me, I buy as much out-of-the box stuff as possible.
A big terrain challenge is variety. While I've collected a lot of Battlefront's excellent terrain, it's still pretty repetitive unless you buy a lot of it. That gets expensive and brings storage issues into the equation. Additionally, if you game at more than one scale and in different genres you've compounded the terrain issues.
There's not much to do for it, except try to get as much utility from every piece of terrain in your collection. For me, at least, having every game feature that same hill and forest with the same cabin gets a little old. I'm especially tired of my GW gaming mat, which is an unvarying green felt covering.
I've been playing a lot of board games recently, and a few of them (Battle of Westros and Descent 2 come to mind) play like mini games. I realized the answer to my variety problems has been right under my nose for a while. The RPG world has a huge variety of setting and terrains suitable for miniature gaming. You just have to be fine with it being flat, 2d stuff.
Not only was I fine with it, but I was also greatly surprised with it. I've invested in a few Gamemastery flip maps as well as some wilderness "dungeon tiles" from WOTC. These provided a whole new variety of terrain for my gaming. The flip mats are good sized, 24x30" of high gloss finish. I tried to take some pictures of a game but glare ruined it. Still, the look was pretty awesome and I was able to have a fight inside a forest, which is not something I get to do too often. I was using the "Deep Woods" flip mat.
I took things a step further and added some 3d terrain to the maps, and things looked even better. I snapped a few pictures of a battle between Dark Elves and Beastmen that I played as part of an on-going campaign. The Dark Elves were raiding the Beastmen camp to recover an important artifact that they had unwittingly in their possession.
This play area is a lot smaller than I usually use. However, I've found that in my solo campaigns I basically have mostly wasted space on the tabletop. Preparing terrain for areas that won't even be the focus of the battle makes little sense to me. Most of the battle with my small sized forces only focus into a small section, about the size you see here. With all the terrain in the way, there was a lot of maneuvering and the small area felt a lot larger.
Well, you get the idea by now. If you like variety and don't mind 2D terrain, you should investigate game mats and dungeon tiles. While these are almost exclusively targeted for fantasy games, I can see many of them being "genre neutral." If you pepper in a few 3d pieces, you'll have some pretty sharp looking tables for your games.
Oh, and if anyone cares, the Dark Elves wiped up twice their number of beastmen. Frenzied Witch Elves, while fragile, are really scary in combat. I'm using Savage Worlds for the game, which easily accommodates Warhammer stats. Anyway, the Beastmen eventually broke and ran off the board.