Anyone who doesn't listen to TMS while watching a test match is doing the whole cricket thing wrong.
I usually listen to sky when they have Bumble on though because he's genuinely really good; and there was a bit in the second innings where Warne really impressed me. It was Australia's second innings in the fourth test when Cook were messing around and not bowling Panesar and doing traditional Cook captaincy; and Warne just explained all of the problems with Cook's captaincy (trying to save runs using the seamers on a pitch which Lyon got a 5 wicket haul on earlier when Australia only needed 200 to win in a day and a half; the awful, overly defensive follow-the-ball fielding sets of Cook and just the overall negativity of England. Warne's always a good guy to have around when a spinner is playing because he'll generally tell you what's accurately happening. He's better on English TV IMO (probably because Channel 9 have no shame in cheerleading, while Sky are a little more impartial); but also because having people from other nations helps to prevent that sort of bias (that's why I like Holding on the Sky coverage of non-West Indian series; and why it was nice to see Bill Lawry on Sky with I think Bumble and Atherton or Hussein; but I could be wrong!
e: ESPN NFL 2k5 has, and always will have the best commentary of any sports game ever, and the people in that are actors!