There is another alternative if you want realistic terrains, skys and vegetation while using poser/daz content.  Carrara works very well with content (some minor tweaking of shaders is sometimes necessary but not a big deal).  Here's a quick example - the terrain is native Carrara - just a few clicks.  Open it full size to get a better idea - also I had to compress pretty heavily to hit the 500k limit so there are some jpg artifacts not in the original.  The content is poser content with two V4s and one M4 thrown in.  The sky is actually Flinks Sky 2, which plays well with the GI and helps with one of Carrara's weak points (clouds).  In addition, you get a pretty good modeler, 3d painting on objects and terrains, an exellent render engine and a broad pallet of good lights.  Of course, it comes at a cost ... what doesn't?

Klebnor

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.