Attempting to distinguish battles from campaigns, and excluding naval and air operations ('coz I'm a "land-lubber") :
Battles:
1) Hannibal, Cannae, 218 b.c. The first and most decisive "double envelopment" manuever; subsequently attempted so many times, but never with the same results -- though Scipio came close against Hannibal himself at Zama.
2) Alexander, Gaugamela (Arbela), 331 b.c. Just about every battle Alexander fought was a display of brilliant leadership and tactics; but Gaugamela stands out for Alexander's ability to adjust and fine tune his battle plans to achieve maximum effect.
3) Napoleon, Austerlitz, 1805. A masterpiece of deception, concentration of force, deployment, and timing. As with so many of his battles, special mention for Davout, the ultimate subordinate commander.
4) Frederick, Leuthen, 1757. The best of Frederick's "oblique order" of attack, using terrain to mask his movement until the decisive onslaught.
5) Lee/Jackson, Chancellorsville, 1863. Hooker's sudden "paralysis of command" notwithstanding, one of history's most desperately daring and successful flanking operations.
Campaigns:
1) Subotai Khan, the Invasion of Central Europe, 1241. The Mongol military system at its best: six independently operating columns converging upon a decisive point, a "Cannae" on the strategic level.
2) Manstein, Plan for the Invasion of France, 1940. The best application of the "Blitzkrieg," marred only by Hitler's inane decision to halt the Panzer columns short of Dunkirk. Special mention for Guderian for his initiative in driving on to the coast, despite OKW's many hesitations after the breakout at Sedan.
3) Heraclius, the Issus/Halys Campaign, 622-623. Turning point in the last Byzantine-Persian War, a superb example of Sun Tzu's admonition to "seize key ground" as well Napoleon's strategy of the central position; and throughout the campaign, Heraclius's judicious choice of when to fight allowed him to turn a basically untrained army into an elite fighting force.
4) Wellington, the Vittoria Campaign, 1813. Much is written on Napoleon's favorite strategy of the movement sur les derrieres, but in my opinion, Wellington's 1813 campaign employed its principles even more effectively than any of Napoleon's campaigns.
5) Scott, the Invasion of Mexico, 1847. Operating deep in enemy territory, Scott cut loose from his base of operations for the final advance on Mexico City. Wellington declared "Scott is lost. He cannot capture the city and he cannot fall back on his base." Having succeeded, Wellington declared Scott the greatest general of the age. Special mention for Col. Robert E. Lee for establishing the lines of attack in the final engagements. Also of interest, the invasion of Mexico provided the exemplar for the better-known Vicksburg Campaign of U.S. Grant.
Honorable mentions for Best Battles/Campaigns (no particular order): Scipio, African Campaign, 204-202 B.C.; Caeser, Gallic Wars, 58-51 B.C.; Saladin, Hattin, 1187; Montrose, the "Year of Miracles," 1644-1645; Prince Eugene, Zenta, 1697; Marlborough, Blenheim, 1704; Napoleon, Opening Phase, Italy, 1796; Napoleon, Ulm, 1805; Jackson, Valley Campaign, 1862; Grant, Vicksburg Campaign, 1863; Hindenburg/Ludendorf, Tannenburg, 1914; Allenby, Megiddo Campaign, 1918; O'Conner, the "Wavell Offensive," 1940.
Worst Battles/Campaigns (no particular order):
Nicias, Syracuse, 415-413 b.c.; Crassus, Carrhae, 54-53 b.c.; the French leadership, in general, Crecy (1346), Poitiers (1356), Agincourt (1415); Burgoyne, Saratoga, 1777; Gates, Camden, 1780; Duke of Brunswick, Jena-Auerstadt, 1806; Bennigsen, Friedland, 1807; Burnside, Fredericksburg, 1862; Hamilton, Gallipoli, 1915; Hitler, Dunkirk, 1940; Hitler, Kiev Pocket, 1941; Hitler, Stalingrad, 1942-1943; Hitler, Kursk, 1943; Hitler, Normandy, 1944; Navarre/de Castries, Dien Bien Phu, 1954.