I have a copy of Draftsight and use it on occasion along with AutoCAD. Very similar feel and functions. I can transfer .dwg drawing files both ways and have not found any significant degradation in data. I have found it very useful if someone sends me an Acad file saved in a newer version than mine. What my Acad will not open, Draftsight will.
To answer Ands43 I agree with JGA, from experience that you can import and re-use your title blocks from Acad.
There is another free 2D program, DoubleCad XT5 which is a product from IMSI. It has two big brothers, TurboCAD LTE 6 and TurboCAD LTE Pro 6 which have a low cost, but function very much like Acad LT. DC has a builtin opening screen with many size drawing templates.
Both work well with Sketchup