There are quite a few different software packages out there that can "render" or digitally paint a picture. Some are quite expensive, others not so expensive. I have three different ones, Bryce 6.1, DAZ Studio 1.8 and Carrara 3D Express.
Most of my early illustrations were created in Bryce. This is a program that can create some very nice landscapes. I've found some good tutorials that I've shared here that use Bryce.
DAZ Studio is a program that is available for free and works quite nicely for isolations and closeups (for me!). I've been able to do more with my lighting and the shading that was available.
Then I recently was able to purchase Carrara. Wow, what a difference! I still had wonderful control over the lighting, but the quality of the render engine and the speed of the render was eye-popping. I could bring out details in the fabrics much easier in Carrara then I ever could in Studio!. The two Regency Dresses are the same pose, different textures. But the main difference is in the detail available in the pink one, which was done in Carrara.
My point? Don't lock yourself into just one piece of software. Get the trial versions and play with them! You'll be amazed at what you can create!