Best Mark (they do phone evaluations as well as on site)
Maritz (you get to talk to a REAL person)
CRI (although they don't pay very well, they do pay regularly) try and combine with another shop, either do 2 for them or some other company
GAPbusters, but off radar right now for me with them not doing Radio Shack
Second to None (If you like Starbucks)
Trend Soruce (business verifications pay the best)
GFK (if you like free gas) they also don't pay very good, but most evaluations are "check the box" not detailed info like CRI
I try and do shops as I do my errands. Somedays I do 4 or 5, somedays none, it just depends on Location,location,location!