The Best VoIP Phone units

I’m sure that this will start a major fllod of responses, so here goes…

What are the best VoIP units to use with Asterisk? I.e. Cisco, Avaya, Grandstream.

What are the least expensive and will get a “basic” setup running?

I’m looking to deploy this in my small office enviroment. I have 4 POTS lines. 3 lines hunt the 4th line is a fax line. I’m looking for some direction on what what phone extensions to use. I want to do VoIP and bring in other extensions eventually from my Sales reps homes.