Actually, comparing Warne, Murali and Saqlain across the period where their careers overlapped is quite interesting. Each player has their own respective strength: Saqlain is the most potent match winner of the 3, Murali is the most consistent, and Warne is the better "big game" performer (looking at WC performance and performance in knockout matches). Saqlain in particular tends to disappear on the big stage.
Murali of course deserves credit for how he's bowled since 2003, but his record is less consistent since then - he's no longer been a consistent threat against all teams (Australia, India, and bizarrely, England have all played him pretty well) and his record in finals has dropped off quite badly.
Murali and Saqlain have better ODI numbers than Warne, but who you regard as "better" is down to personal preference. Warne certainly has the "big game" factor that's lacking for both Saqlain, and to a lesser extent, Murali.