I suggest you spend some time reading the volumes of posts on this subject.
Be prepared to spend some time:
http://www.talkbass.com/forum/search...earchid=845341
The most popular heads are probably Acoustic Image and Euphonic Audio. Cabinets? There are a zillion choices and no such thing as the perfect rig. All equipment will have some compromise and you will need to find the right amplification for YOUR needs. The experiences of others can inform you, but you won't really know until you dive in yourself.