Professionals use a few, the big 3 however are:
Autodesk 3D Studio Max
Autodesk Maya
Avid SoftImage XSI
Those are the big 3, certainly the ones used in the gaming and movie industry. I myself use 3D Studio Max as I find it has the most useful interface, but they all have good and bad points.
I believe Maya will be merging with 3DSMax for 3DSMax10, so I would go with 3D Studio Max, mainly down to interface reasons, I find SoftImage horrendous, though I find SoftImage the best for animation, certainly with the addition of slider bars which make lip-syncing a lot easier, however I don't like the way you have to texture in SoftImage. Horses for courses I guess.
As for renderers, those programs have them built in, but there are seperate ones which are highly regarded, again, a big 3 if you will:
Brazil
Maxwell
vRay
Personally I use Mental Ray in 3D Studio Max, I find I can get pretty much what I need from that as I don't do photorealism or intricately detailed rendering, which is what the 3rd party renderers are known for. You will find out more information regarding the renderers on Wikipedia, but you won't need them to begin with (nor may you need them later).
If you need any help throw me an e-mail or contact me on MSN (would prefer e-mail though). E-mail is the same as my MSN address.