V-Carve Pro for sign making. Nothing else compares.
I have V-Carve Pro, Cut 2D and Photo V-Carve from Vectric. Love all of them. Simple but powerful programs with very short learning curves.

I Also have:
Solidworks Premium 2009
Mastercam X3
AlibrePro with AlibreCam

I also have just about every freeware cad/cam and graphics package available. After working with them for a while, you will understand why they are freeware!

Look into Cut3D and Aspire for 3D modeling, but you might find all the 3D models you need on sites like Vector Art 3D.

For sign making, you won't be disappointed with V-Carve Pro.

Make sure you also get Mach3 to run your cnc - about $175 but will save you all the headaches using cheaper or freeware programs, plus it's fully compatible with Vectric software.

Continuing with "free" software, check out CNC4Free:
http://cnc4free.org/
All the best free stuff is there, as well as an excellent set of tutorials which will help you with whatever software you end up with.

Good luck!