One solution would be a portable CD-RW. These are a little more expensive, say $300, but can be plugged into a USB port . This would let you move it from your desktop to your laptop and carry the whole thing with you. The software that comes with it lets it be used like a floppy only vary much larger.

I have not used Legacy although I think it is the basis for Personal Ancestral File that LDS gives away free. I am currently using The Master Genealogist and I have Family Tree Maker installed on my machine. I use FTM for special projects, for instance, if I don't know whether a family fits in my lines I will park it in FTM until I get ready to out it in the main database. I started with Roots and went through the whole move from Roots to Ultimate Family Tree.

If you haven't looked at Personal Ancestral File, I would test it out. (The price is right ;-)