I think (!) my original point was that if you were listing certainly the top five right backs in European/world football of the last 30 years, Lahm is quite obviously going to get into pretty much everyone's list, unless they've had some kind of a breakdown or are Garth Crooks. In fact you could probably make that top three. I wouldn't say that would apply to Alonso, though I'll accept that he has a lot more competition, not least because there are so many different varieties of "central midfielder" (is he better than Matthäus was, well you can't really make that comparison).
Not a dig at Xabi per se because he's an absolutely fantastic footballer and a top guy as well. Incomprehensible really how Liverpool got him for so cheap. £10.5m was a fairly mid-ranking fee even back in 2004. Chelsea spent more in that window on Paulo Ferreira (who was fine and all that until his legs went, but he was just a decent RB, nothing more).