It really depends on what you are trying to do --
I have played very little with Bryce and Maya (if anyone has better input here, give me a heads up), and those programs seem to be built to do 3D landscapes.
Strata 3D Studio pro can do just about everything you want, and I think it is a great program.
Lightwave 6 is a more advanced program because of the massive amount of control you can do -- meaning hours and hours of meticulious control that is annoying as hell. One of my friends works over here by me at Pixar and he spends hours working on that thing... &%@* crazy.
I would say for what you are doing, use Strata. It's a powerful program, with a nice learning curve that can do just about anything that Lightwave can do. Start off with Strata -- it's cheaper (alllooootttt cheaper, and it doesn't need one of those key plugs that goes in the back of your computer -- unless you know how to hack those things) and very powerful... and many people, like me, prefer to use Strata and stay far away from Lightwave whenever possible.
A couple years ago when I did designs for Snap-On, they requested that we use Strata -- if you want to view what it can do, there's a couple images here for the old company I worked for in Chicago. Go to fricknet.com
- on their jump menu, scroll to the bottom to graphic design. You'll see some 3D stuff we did that was very cool, and much quicker than Lightwave.
By all means, if you want to play with Lightwave later on, go ahead. But I would say use Strata -- I prefer it.