I am brand new to th CNC scene. I am interested in purchasing an off the shelf CNC machine for creating 2 dimensional designs in wood. I assume you would call it "signwork" with the possibility of moving into doing inlays in the future. This would be at the hobby to small business level.

I am interested in creating designs on wood boxes specifically. Approximate dimension range would be 3'x2' and about 4 -7" deep.

What type of machine should one buy to get their feet wet. I have strong computer skills (Computer Science Masters) and a PC at home I could possibly use to program the machine. I do not have a strong woodworking background but have the ability to learn and I am pretty handy at building things. I don't think I want to build a machine myself because I really want to hit the ground running.

Does anyone have suggestions on what type of CNC machine I should look for without completely destroying my bank account?

Shopbot, but I don't know what amount of money will destroy your bank account.
For a commercially built machine, the size you want you will need to spend anywhere from $6000 to $9000.

http://www.k2cnc.com/machines/KG-3925_detail.html

Ony 5" Z, though, and you'll have to add motors and drives.