ya giz, I'm with mr pimp on this one. Banner grabbing is not without it's usefulness. Portscanners sometimes have banner grabbing built in, and if you don't have any idea what the banners may tell ya, then it's worthless to ya. Don't dis working techniques just because you personally rarely have need for them.
AND, I have more respect for people who target an IP/computer and methodically examine all the ports and their banners than for opportunists who scan a whole IP range for an open port.