Refinement makes a good tool even better. The 4-1/2-inch W8-115 Quick Angle Grinder (model MET-A-9415) from Metabo features repositioned brushes and a fan that pulls 35% more air through the tool, helping to improve both performance and tool life, according to the manufacturer. Design improvements include tool-less grinding wheel changing and wheel guard adjustment, spindle lock, and a safety slip-clutch to prevent kickback when the grinder snags or binds. Price: $129. 800-638-2264.