Ask HN: best mobile broadband or tethering?

as usual, you guys are smart and know your stuff, so i trust your opinions. i've gone looking for current info on this, but have come up short.

i'm looking for the best available mobile broadband or smartphone with tethering (or any other viable option). i'm looking at the possibility of doing 8 hours of work a day while on the road, so something with a 5mb cap + $1/mb overage is right out. i'm also able to wait if something shiny is coming out in the near future.

anyone have any thoughts or experiences? i'm willing to consider most things, including something more expensive for better quality.