Think about what sort of place this is? Is it a good place or a bad place. If its a good place, then you might want some greenery and some yellow lighting. If its a bad place, dead trees or bones. Add some red/orange lighting. As far as modeling, I use Truespace 6 (www.caligari.com). There are free demos somewhere, think there was a thread on that here. Might be a free full version out there too. Agent smith might know something. Truespace does real booleans, so you are not overwhelmed with too many wireframes. More than one type of metaball primatives too.