Don't let this page put you off. 3D Coat is excellent value. Yes, it's a bit strange but they are honest people:
http://3d-coat.com/company/our-voice/I'm biased to Linux. That's all I use now so all these apps are Linux as well as Windows and OSX.
All round best app including value (considering it's aiming at trying to be an industry standard app) is Modo but it's still not that cheap.
3D Coat can't be beaten for sculpting purposes (considering cost) but it's actually still be best in some areas as far as I'm concerned.
Blender is a must have no brainer. You can do a whole lot with that app. There are a some deficiencies and that's why Modo is much better but Blender can do a few things that other apps can't. It's got much better with cycles rendering engine which I think gets awesomely realistic results. In fact once Blender cycles gets voumetrics it starts moving back to being decent for landscape again. Most people don't get this but some of these programs can achieve similar results to Terragen or Vue now and with less hassle and all the other extras you get with these kinds of programs. That's one reason I stopped using Terragen and didn't upgrade but that's a whole other story. I've abandonned the procedural planetary scale type idea. Blender isn't quite there for this but I expect it will be eventually with various updates needed for cycles.
One of the best basic modelers is Wings 3D but you have to spend some time working it out. Once you do it all makes sense.
I'd drop Hexagon if I were you. I have that from years back but I haven't used it for years. It had massive potential but ended up a reliability disaster.