By looking from this post title, maybe u askin "Why only semi-migration? Why not full migrate to Ubuntu? Hehe there r still other factors that keeps mi avoid to use only Ubuntu as OS.
At 1st, i only wan try ubuntu using flashdisk with my friends (try http://unetbootin.sourceforge.net/ if u wan booting use flashdisk) but after i try it finally i decide to fully install it because if booting thru flashdiskm any setting will b reset after restart. So i dual boot it with Vista cause in Ubuntu i still got some drivers n application error.
It also troublesome sometime, after install it codec for audio n video nt found, so i must go update it. I also only noe sudo wvdial at terminal still very noob here. Hehe just learning use it.