Everywhere I've seen, Battlefield in a Box stuff is sold out.  I got 1/35 brick walls from Tamiya that are a pretty good match.  $5 a box, 3-4 boxes will be a good bit of terrain.  Also got some Secret Weapon damaged Jersey Barriers ($8 for 5) that I really like.  Still can't beat Op. Cerberus for some buildings though.  And can always sell/trade the heroes.

Look for 28mm, 32mm, 1/48, O scale, or 1/35 (slightly large) terrain from model, miniature, and railroad companies. 

I have the Battlefield in a Box River Set and the scale isn't that bad. I also have some of the Hill pieces, the only problem is that they are only 2" high which doesn't give the walkers much cover to manuever around. I'm in the process of creating some hills out of styrofoam.

I see alot of plasticville stuff on ebay, is it the right size?

spoook said:

For railroad terrain make sure it is "O" scale. 

The "O" scale Plasticville stuff my local train shop carries looks great, but it is very expensive new.

spoook said:

As ItsUncertainWho mentioned, as long as it is O scale or O gauge you are in good shape. I have several Plasticville O scale buildings that I picked up on the cheap that work pretty good for terrain. There's a Police Station, Hospital, Train Station, Bank, Airport Terminal w/Tower and Hangar that all work great and have a nice late 40's / early 50's vibe to them that works well with Dust.

Keep checking on Ebay, particularly for bundles or lots of old used stuff. Sometimes you can pick them up in bulk for low cost if you don't mind doing a little cleanup and/or repair.

I've used a lot of both Pegasus and BFIAB stuff, and I love it.

What I have:

Pegasus:
Bridge (I think it's called sci-fi bridge or something like that - only item on this list that came unpainted)
Craters
Oil drums
sandbags
Barbed Wire

Battlefield in a Box:
Rivers
Gothic Ruins (I have Large, Medium, and Small corner ruins)
Rocky outcrops
Large Rock.

If got into Dust Warfare a year ago when it came out, and it was my first miniatures game.  I wanted some good terrain quickly, and so I meant mainly with Pegasus and Battlefield in a Box, and am very happy with what I ended up with.  Great looking scenery, most of it came prepainted so was no work to set up.  It's all well made, and very well painted considering the price.  I highly recommend both companys' work for Dust Warfare.

Also, if you want something cheap, fairly easy to assemble, and it looks great, get these papercraft bunker walls:

http://boardgamegeek.com/filepage/61124/papercraft-bunker-walls

Print them out onto card stock, cut out and glue.  They look great, and if you play Dust Tactics at all, they are designed specifically for that game and fit perfectly in the grid squares.

I also use Woodland Scenics trees.  Trees are pretty scale-neutral, but get their larger ones and they are pretty nice.  If you get the tree armatures and the foliage, you can make your own pretty easily, or they sell them pre-made.

felkor said:

It's called the techno bridge. I personally don't think it works well with the river, as it doesn't completley clear the river sitting flat. If I ran a company creating 28mm terrain, then I would make sure they are all compatiable. The bridge also seems big for it's scale. It's 12 inches long and will take a minimum of 1 turn for a normal unit to cross. 2 turns if your not at the foot of the bridge. Walkers have plenty of room to cross, it just feels a bit big overall.

I also purchased the pegasus gothic building and was unimpressed. Lots of denibbing to do, and it doesn't have enough walls to make the building pictured on the box.

My next purchase will not be from pegasus. 

I don't have the Pegasus river, but the Techno Bridge is about the perfect size for the Battlefield in a Box bridges.  It works perfectly.  The length is also adjustable - you can make the bridge shorter, or if you'd like, buy multiple bridges and make it longer.  I painted mine up and covered it in lots of rust, and it's now one of my favourite terrain pieces.

For buildings and rivers though, I agree, I didn't like the look with Pegasus' versions, so I went with Battlefield in a Box instead.  I do like Pegasus' barbed wire, sandbags, and oil drums though.  They add nice little touches around the battlefield, and the sandbags and barbed wire fences are even right about the same dimensions to fit the fortification rules in Dust Warfare.