You should definately decide if you are looking for a 1.x viewer for performance, or a more modern viewer. Generally the 1.x viewers will give better performance on weaker machines, but lack features compared to the v3 viewers.
For 1x viewers, pheonix was the popular choice, but they have announced plans to stop updating reliably, so CoolVx or singularity are popular alternatives.
If you have a machine with the horsepower and are ok with the newer interface, you probably want a V3 browser, firestorm generally being the most popular here, though I have been using exodus lately and enjoyed it.