There's a few out there for him to use and as a GC he certainly doesn't need a $2-3K piece of software because there's alot more out there now than there ever was. If he's only using them to create general plans (not doing any seriously complex 3D rendering or anything like that) then here's a few I'd recommend.
TurboCAD Pro V12 - ($500) You can get the Deluxe version but for a GC it's too watered down IMHO, here's a comparison of the two side by side
http://www.turbocad.com/whatsnew_v12.asp?mcid=370 ). The full version is quite sophisticated and can do alot of things including 3D rendering if needed.
The rest are from Autodesk
AutoCAD 2007 full or Architectural Desktop 2007 - (very expensive) This is probably what the GC was talking about when he mentioned software being $2-3K per seat, it's very expensive but has excellent 2D and 3D capability. For a GC they are probably overkill though.
AutoCAD LT 2007 - ($800) This is really a standard in the drafting field and has been around for a long time. If you're looking for a really professional drafting tool, this would be the better choice (has more features to save you time when drafting like auto dims or perspective view).
AutoSketch 9 - ($100) This is strictly a 2D program and it's quite limited but if you need something really cheap and will never need to transfer drawing files or do any 3D work, then this program might be ok.
Either TurboCAD Pro or AutoCAD LT would be my choices for the GC, but be careful buying student versions because they often have features cut out. You're better off paying more for the non-academic version (at least with AutoCAD) because when you print stuff out it will put "Student" all over your drawings and often tech support goes seriously lacking when you call and give them the S/N and it shows student version. Neither is good in a professional setting.