I have plantar fasciitis so have tried lots of options. Sketchers go walks are so comfy and seem to take pressure off the heel even though they don't have a huge arch support. I also have fit flops (only in flip flop sandal style though) which are fabulously comfy. they redistribute pressure around the sole of the foot and it really works. birkenstocks are good for it too, but probably not suitable for your work.
try some sketchers on to see which fit you best: the go walks are i think quite wide (ok for me, but i've got big feet) so the lace ups might be best for all-day wear.
good luck with the PF - i've had it now for 5 months, and the last few days it seems to have got a bit better so fingers crossed it's going.