In my experience, there are really only five 3D modeling packages that are worth really knowing: Siemens' NX, Dassault Systemes' CATIA and Solidworks, PTC's Creo (formerly PRO/ENGINEER), and to a lesser extent Autodesk's Inventor. The first four are basically industry-grade packages, so you'll run into them a lot. I've seen AutoCAD's 3D modeling a few times, but for drafting I've seen it a lot. It's still the best 2D drafting package out there. CAD licenses cost a lot for sure, but if you're a student, Autodesk gives student copies of Inventor away for free.
I don't think Google SketchUp is something I'd put on a resume. I've tried it and it's not really meant for CAD per se. Like all Google products, it's a product they developed for a while, released it as a beta, then let everyone make up their minds about how they were going to use it. I don't think it will ever be a real industry product (although Trimble thought it was good enough to acquire), so I don't think any potential employers will lend any weight to you being able to use it.