My much debated analysis belongs in this thread.
Points in Favour of Murali
1) Warne has failed dismally against the best players of spin – India (43 wickets at 47.18). Murali has done far better against them (51 wickets at 32.94).
2) Murali has a better average, strike rate, economy rate, and takes more wickets per match than Warne; despite the fact that Warne has not had to play against the world's best team.
3) Murali has a better record against all countries, except South Africa and Pakistan.
4) Murali is far more consistent. Warne has been known to be hammered occasionally and although Murali has previously been nullified to a degree, he is very rarely hit around the park.
Warne
45 7 150 1 3.33 3rd Test v Ind in Aus 1991/92 at Sydney
30 7 122 1 4.07 1st Test v Ind in Ind 1997/98 at Chennai
42 4 147 0 3.50 2nd Test v Ind in Ind 1997/98 at Kolkata
34 3 152 1 4.47 2nd Test v Ind in Ind 2000/01 at Kolkata
42 7 140 2 3.33 3rd Test v Ind in Ind 2000/01 at Chennai
30 6 108 2 3.60 3rd Test v SA in SA 2001/02 at Durban
38 7 129 3 3.39 2nd Test v SL in Aus 2004 at Cairns
32 4 115 2 3.59 1st Test v Ind in Ind 2004/2005 at Nagpur
Murali
36 6 123 1 3.42 1 L 1st Test v Pak in SL 1994 at Colombo
54 3 224 2 4.15 2 L 1st Test v Aus in Aus 1995/96 at Perth
33 6 136 0 4.12 1 L 1st Test v NZ in NZ 1996/97 at Dunedin
5) Warne is part of a stronger bowling attack. If Warne was of equal ability to Murali he would take less wickets per match than Murali (because there are four good bowlers competing for wickets), but would have a lower average and strike rate (because greater pressure is put on the batsman by bowlers at the other end). For an example of this take two great fast bowlers, Marshall and Hadlee - Marshall having a better average because the high class West Indian bowlers put greater pressure on the batsmen, but Hadlee took more wickets per match because there was less competition for them. Same with Lindwall vs Bedser, Ambrose vs Akram, Laker vs Tayfield, and many, many others. Murali takes more wickets per match and has a lower average and strike rate.
6) A high proportion of Warne's test wickets are numbers 10 and 11 in the batting order; Murali does well against all batting positions. When they were both on 527 wickets, Warne had taken the wickets of batsmen 8-11 190 times, Murali had done it 162 times - a significant difference of 17%. And we all know it is far more valuable to be able to defeat players of high ability, because they can really make you suffer. Tailenders will usually get out sooner rather than later anyway, and very rarely turn a match on its head (with the bat anyway). What’s the point in Warne taking the wickets of Nehra or Walsh game after game, if he cannot trouble Tendulkar or Lara?
7) Although Warne has been less effective since his shoulder injury, even at his peak (1993-97) he was not as good as Murali has been this century.
Mat O M R W Ave Best 5wi 10w SR Econ
Murali 2000-2003 37 2347.3 684 4990 258 19.34 9-51 22 10 54.5 2.13
Warne 1993-97 57 2876.5 938 6457 277 23.31 8-71 11 3 62.3 2.24
8) Murali on top form is more devastating than Warne on top form.
Best innings:
9/51 M Muralitharan v Zimbabwe at Kandy, 2nd Test, 2001/02 [1583]
9/65 M Muralitharan v England at The Oval, Only Test, 1998 [1423]
8/71 SK Warne v England at Brisbane, 1st Test, 1994/95
8/87 M Muralitharan v India at Colombo (SSC), 3rd Test, 2001 [1559]
Best Series:
Murali
Sri Lanka in Pakistan, 1999/00 [Series]
3 213.1 516 26 6/71 19.84 2.42 49.1 1 1
South Africa in Sri Lanka, 2000 [Series]
3 227.4 480 26 7/84 18.46 2.10 52.5 3 1
Zimbabwe in Sri Lanka, 2001/02 [Series]
3 203.1 294 30 9/51 9.80 1.44 40.6 2 1
England in Sri Lanka, 2003/04 [Series]
3 231.4 320 26 7/46 12.30 1.38 53.4 1 1
Australia in Sri Lanka, 2003/04 [Series]
3 209.1 649 28 6/59 23.17 3.10 44.8 4 1
Warne
The Ashes (Aus/Eng) in England, 1993 [Series]
6 439.5 877 34 5/82 25.79 1.99 77.6 1 0
The Ashes (Aus/Eng) in Australia, 1994/95 [Series]
5 256.1 549 27 8/71 20.33 2.14 56.9 2 1
The Ashes (Aus/Eng) in England, 2001 [Series]
5 195.2 580 31 7/165 18.70 2.96 37.8 3 1
Australia v Pakistan Test Series in Sri Lanka/U.A.E., 2002/03 [Series]
3 124 342 27 7/94 12.66 2.75 27.5 2 1
Australia in Sri Lanka, 2003/04 [Series]
3 168 521 26 5/43 20.03 3.10 38.7 4 2
The Ashes (Aus/Eng) in England, 2005 [Series]
5 252.5 797 40 6/46 12/246 19.92 3.15 37.9 3 2
9) You could take a look at their respective records in the English county championship (note Murali was by far the star bowler in every season he played, while several Hampshire bowlers took wickets more cheaply than Warne in all his seasons):
Mat B M R W Ave Best 5wi 10w SR Econ
Murali 25 7695 391 2735 185 14.78 7-39 21 6 41.5 2.13
Warne 36 8423 323 3858 162 23.81 6-34 9 0 51.9 2.74
10) One reason why Warne is rated so highly is Gatting’s reaction to the so called “ball of the century.” The shock that that ball sent through the cricketing world was immense because it was thought no one else could bowl that delivery. Actually, Warne was not the only one to bowl such a delivery in recent years, Abdul Qadir had bowled the same delivery a few years earlier, it just wasn’t highlighted at the time because it wasn't on such a big stage. Murali bowled similar balls which were every bit as good to both Sadgapan Ramesh and Mark Butcher a few years ago.
Warne constantly gets so many accolades/awards that he doesn't deserve, purely through a God like reputation galvanised by ill educated media hype. In truth, his career has been highly inconsistent, he has constantly failed against the best, benefited from the opportunity to nail tails after McGrath and co have dismissed the better batsmen, and his overall career figures fall short of the truely great category.
Points in Favour of Warne
1) Has much greater competition for wickets, and yet still has more victims than any other Test bowler in history.
2) Has not had the opportunity to destroy Zimbabwe and Bangladesh. Murali has taken over a fifth of his wickets against these teams while Warne has played a combined total of 2 matches against them.
3) Has a better average and strike rate outside Sri Lanka than Murali.
4) Recognised by the (biased) Anglo-Australian media as the best spinner of all times.
5) At his peak he had more variation than Murali.
6) He has a better record away from home than Murali.
7) Does not get the opportunity to play half his matches on dustbowls.
Conclusion: Murali > Warne