I browsed through my address book, looking for the most frequent first names and surnames of people who I know. There were around 3,000 first names and 6,000 surnames altogether (of 7,500 contacts). The list below has the top 55 first names and top 57 surnames (I was aiming for top 50, and this was the closest I could get that was reasonably neat). The first names cover 1700 of my contacts; the surnames only 500 - so surnames vary a lot more than first names; the top surname occurs 19 times, the top first name 104. I did not break down by gender overall, but 38 of those first names are generally male, 16 generally female, and Chris, Alex and Jan might be either (though most of them on my list are men) - so women's names vary a lot more than men's names; the top male name appears 104 times, the top female and might-be-either names both 34. At the other end of the scale, not shown here, there were 2000 unique first names and 5,200 unique surnames.
I know two Andrew Smiths, two Paul Taylors and three Andrew Wilsons. (Down the list a bit, I also know two Siobhan McKennas.) I do actually know a David Smith, combining the top first name and surname in the table. There are some other neat coinidences reading across - Peter Robinson, Stephen King. Some of the surnames (Murray, Whyte, Mace, and Minchin) are boosted by my relatives.
The results are more Anglophone than I had anticipated, with Schneider, Meyer, Cohen and Frank the only surnames not of obvious British/Irish origin in the top 50 (Klein, Ahmed and Hartmann just missed at 5 each, and actually although Minchin often is a English-origin name, in this case it's originally from elsewhere). Stefan is the only first name in the top 50 with a non-English spelling (again, next step down would have had Andreas and Ana-with-one-"n" on 15; the top Irish name, Sean, was on 13, with Niall and Fiona on 10; a lot of names of course have a standard spelling in other languages which is the same as English). I guess that although I know a lot of people from non-English speaking countries, I don't know enough from any one of those countries for them to be visible at this level. (As already mentioned, Ana was a near miss at 15; Tanja and Goran a little further down at 12; the top Slavic surname is Ivanov at only 4.)
Anyway, a harmless and mildly amusing bit of number-crunching.