Here's the all-time list as of the start of the 2008 season:
CAREER
AT BATS >= 1000
AVERAGE AVG AB
1 Joe Jackson .375 2498
2 Tris Speaker .354 5546
3 Nap Lajoie .339 6034
4 Lew Fonseca .337 1494
5 Riggs Stephenson .337 1034
6 George Burns .327 2611
7 Eddie Morgan .323 2282
8 Roberto Alomar .323 1748
9 Earl Averill .322 5915
10 Joe Sewell .320 5621
11 Johnny Hodapp .318 2237
12 Charlie Jamieson .316 5551
13 Manny Ramirez .313 3470
14 Joe Vosmik .313 3207
15 Hal Trosky .313 4365
16 Dale Mitchell .312 3960
17 Charlie Hickman .309 1482
18 Dick Porter .308 2250
19 Bruce Campbell .305 1889
20 Rico Carty .303 1487
21 Homer Summa .303 2844
22 Minnie Minoso .302 1156
23 Victor Martinez .301 2392
24 Larry Gardner .301 2306
25 Kenny Lofton .300 5045
26 Carlos Baerga .299 3666
27 Elmer Flick .299 3533
28 Jeff Heath .298 3489
29 Ted Easterly .297 1123
30 Julio Franco .297 4282
31 Joe Wood .297 1456
32 Lou Boudreau .296 5754
33 Albert Belle .295 3441
34 Pat Tabler .294 2476
35 David Justice .294 1713
36 Bill Knickerbocker .293 2030
37 Odell Hale .293 3575
38 Mike Hargrove .292 2945
39 Johnny Burnett .292 1629
40 Travis Hafner .291 2258
41 Roy Hughes .290 1250
42 Miguel Dilone .289 1244
43 Roy Weatherly .288 2430
44 Jack McCarthy .288 1117
45 Vic Power .288 2123
46 Jimmy Piersall .288 1287
47 Ben Chapman .288 1093
48 Brett Butler .288 2302
49 Coco Crisp .287 1626
50 Jim Thome .287 4640
51 Ellis Burks .287 1155
52 Frankie Pytlak .286 2032
53 Braggo Roth .286 1423
54 Larry Doby .286 4315
55 Al Rosen .285 3725
56 Freddy Spurgeon .285 1176
57 Ron Belliard .285 1485
58 Tito Francona .284 2926
59 Willie Kamm .284 1785
60 Bobby Avila .284 4356
61 Roy Cullenbine .284 1072
62 Omar Vizquel .283 5708
63 Grady Sizemore .283 2061
64 Mickey Vernon .283 1029
65 Mel Hall .282 1765
66 Chris Chambliss .282 1520
67 Elmer Smith .281 2185
68 Les Fleming .281 1283
69 Toby Harrah .281 2577
70 Eddie Murray .281 1205
71 Gene Woodling .280 1164
72 Lyn Lary .279 1214
73 Alan Bannister .279 1219
74 Ray Chapman .278 3785
75 Vic Davalillo .278 2335
76 Sandy Alomar Jr. .277 3409
77 Harry Bay .276 2465
78 Ken Keltner .276 5655
79 Glenn Myatt .275 2317
80 Hank Edwards .275 1439
81 Travis Fryman .275 2184
82 Vada Pinson .275 1140
83 Duane Kuiper .274 2865
84 Oscar Gamble .274 1192
85 Buddy Bell .274 3712
86 Luke Easter .274 1725
87 Brook Jacoby .273 4314
88 Jerry Browne .273 1401
89 Bob Kennedy .273 1559
90 Doc Johnston .273 2557
91 Bill Bradley .272 4644
92 Ron Hassey .271 1690
T93 Vic Wertz .270 1591
T93 Oris Hockett .270 1665
95 Tony Horton .269 1878
96 Ray Fosse .269 2039
97 Al Smith .269 2407
98 Joe Carter .269 3256
99 Ben Broussard .268 1650
100 George Hendrick .267 2047
101 Rocky Colavito .267 3185
102 George Vukovich .267 1183
103 Jody Gerut .267 1099
104 Jim Norris .266 1108
105 John Ellis .266 1210
106 George Stovall .266 3587
107 Jhonny Peralta .266 1914
108 Joe Azcue .266 1904
109 Leon Wagner .265 2189
110 Steve O'Neill .265 4182
111 Rollie Hemsley .264 1302
112 Tony Bernazard .264 1794
113 Casey Blake .264 2656
114 Rick Manning .263 3997
115 John Romano .263 1891
116 Nig Clarke .263 1204
117 Joe Gordon .262 2021
118 Paul Sorrento .261 1566
119 Luke Sewell .259 3195
120 Einar Diaz .259 1455
121 Mark Whiten .259 1024
122 Ray Boone .259 1600
123 Bill Wambsganss .258 4191
124 Mike Rocco .258 1721
125 Chico Carrasquel .257 1022
126 Fred Whitfield .257 1866
127 Matt Lawton .257 1381
128 Jose Cardenal .257 1140
129 Chuck Hinton .257 1740
130 Carmelo Castillo .256 1152
131 Felix Fermin .256 2017
132 Harry Bemis .255 2229
133 Joe Birmingham .254 2631
134 Terry Turner .254 5783
135 Andre Thornton .254 4313
136 Roy Foster .253 1016
137 Ivy Olson .252 1692
138 Chico Salmon .252 1304
139 Joe Evans .252 1303
140 Tom Veryzer .251 1449
141 Jack Graney .250 4705
142 Graig Nettles .250 1704
143 Rube Lutzke .249 1876
144 Bubba Phillips .249 1412
145 Woodie Held .249 2800
146 Max Alvis .249 3514
147 Harry Simpson .246 1120
148 Dick Howser .246 1246
149 Andy Allanson .246 1204
150 Charlie Spikes .246 1848
151 Cory Snyder .245 2431
152 Eddie Leon .243 1417
153 Jack Brohamer .239 1501
154 John Lowenstein .239 1790
155 Bill Hinchman .238 1435
156 Larry Brown .238 3014
157 Duke Sims .236 1561
158 Ray Mack .233 2630
159 George Strickland .233 2111
160 Frank Duffy .233 2503
161 Willie Kirkland .232 1371
162 Bob Lemon .232 1183
163 Jim Hegan .230 4459
164 Chris Bando .227 1282
165 Pat Seerey .223 1471
166 Mel Harder .165 1203
167 Bob Feller .151 1282
Ivan Rodriguez has a career batting average of .298.
Babe Ruth's career batting average was .342.
Wade Boggs had a career batting average of .328 and Don Mattingly had a career batting average of .307.
As of 2009 Robinson Cano has a career batting average of .306
Keith Hernandez had a career batting average of .296. He had 2,182 career hits in 7,370 career at bats.
Babe Ruth had a career batting average of .342 with 8,398 at bats.
Willie Mays had a career batting average of .302, 3,283 hits in 10,881 at bats.
Through August 12, 2016, Alex Rodriguez has a career batting average of .295.
Sammy Sosa had a career batting average of .273.
Pete Rose's career batting average was .303 (4,256 base hits on 14,053 at bats).
Hank Aaron had a career batting average of .305 (3,771 base hits in 12,364 at bats).
Ty cobb has the highest career batting average at .366