Well, it is interesting to see how people change their opinions with time (and also based on the place they are at.). In 2001, I distinctly remember both Warne and McGrath claim that Sachin was the best in the world quite easily. Warne actually said something like Sachin is 1st, Daylight is 2nd and Brian Lara is 3rd. But now, after announcing his retirement, he has mentioned that Lara and Sachin are both the best. McGrath himself was generally claiming Sachin to be the best in the world circa 99 and even upto 2001. From then on, it went to "both Sachin and Lara are the best" in 2004 and now, after announcing his retirment, he has said that he will put Lara slightly ahead of Sachin.
Lara, IIRC, in one of his interviews 2 or 3 years ago, claimed that Wasim Akram and Murali were the best bowlers he has faced. Wasim the best fast bowler and Murali the best spinner. Now, he thinks Warney is the best.
And also, when Warney and McGrath made those glowing praises about Sachin, it was either that they were in India or that India were touring Australia. Is it a coincidence?
Also, is it a coincidence that Lara speaks so highly of Warne in his hometown?
But, to speak more seriously, Lara has been quite vocal in his praise for Warney over the past couple of years. In fact, IIRC, he was the only one apart from the Australian team who spoke up for him in the 2003 WC about his drug ban and stuff. And Warney for his part has been more than just glowing in his assessment of Lara in the recent past. I guess they just realized how good each other was rather late in their careers.