I guess it depends on what you consider expensive.
Dr. Scholls gell inserts are pretty nice, but they won't make a $59.00 pair of boots from Wal-Mart feel like a pair of top end Wolverines. Red Wing makes some pretty nice boots, but I've gone through too many pairs too soon. The stitching comes apart as soon as they get spatter and dross on them from welding and cutting.
Most comfy and agile I've had ever are a recent pair of Timberland Pro 263 with some kind of alloy toe and vibram soles @ 120 bucks. I really like them and with fall mushroom hunting season on right now, have put some hard miles through pretty much everything on them.
Carolinas logging boots are tough as hell too, but not tooo comfy until your feet get broken into them. They are absolute hell on concrete shop floors though.
edit: Rule of thumb I use- Hard surface needs soft rubber sole, soft surface(dirt/mud, grass) needs hard rubber sole