Blackberry Bold simply because it's a free perk of the job. Now that I say that, I'm not sure that statement is entirely true...
I have the EnV2 POS. If you aren't familiar with that model, the POS stands for Piece Of Sh!t. Its a free work phone/service, so I can't complain too much.
HTC Hero on the Sprint Network and I couldn't be happier. I had an EnV2 through Verizon and I have NEVER been so happy to get rid of a phone or the carrier in my life. Verizon's prices have become ridiculous!! I am paying almost the same amount for my plan now which includes unlimited internet, unlimited text,pic, and video messaging, unlimited mobile to mobile calling on ANY network, and with Verizon I didn't have any internet and my unlimited mobile to mobile was restricted to the Verizon network.
I agree Sprint is the best plan ...and it piggy backs off Verizon's towers so you get the same or better coverage ....
HTC Evo (Droid)... I watch college football on ESPN from a tree stand. No more tough decisions on Sat mornings!!