Best Tennis Serve Ever?

Watching Andy Roddick hit serves at up to 150 mph at the SAP Open in San Jose this winter, I wondered what is the most impressive serve ever? 

Roddick has the sheer speed record of 155 mph from a 2004 Davis Cup match against Vladimir Volchkov, having several times eclipsed the earlier record of 149 mph that he shared with Greg Rusedski. 

But, hey Roddick weighed a muscular 210 pounds back then, although he's slimmed down to 185 of late. He should be able to hit the ball hard. So, I'm proposing a new if semi-facetious way to judge the fastest serves: By the pound or by the inch, or maybe by age. 

Here are my nominees for most impressive, fast serves: 

1) Nikolai Davydenko claims to weigh 150 lbs, but that must be soaking wet and with his tennis bag on his back. In beating Rafael Nadal in the Miami Masters final, Davydenko hit a 138 mph serve. That's equivalent to Roddick hitting one 180 mph. 

2) Daniela Hantuchova has "bulked up" to 137 lbs of late (and I believe that as much as I believe that Serena weighs 150 as her bio claims). But back when he was so skinny people worried about anorexia, she weighed 116 pounds. When I watched her win at the Bank of the West tournament at Stanford University, Hantuchova flexed her number-ten Ticonderoga biceps to crank out a 110 mph serve. That's an impressive 94% of her weight, or equivalent to Roddick serving at 199 mph. 

3) Turning to height, Bjorn Phau is perhaps the fastest player on the tour, but at 5 ft 9 inches the German is also one of the shortest. Yet when he nearly upset Nadal in the first round of the 2008 U.S. Open he blasted a 136 mph serve. 

4) The other dimension is time: Brenda Schultz-McCarthy had a big serve when I saw her play then teen-ager Martina Hingis in Oakland. 

McCarthy retired for several years, then came back to the set the speed record for women's tennis (No, it's not held by Venus Williams as the announcers keep repeating).  

In July 2006, at the age of 36, Schultz-McCarthy claimed her place as the fastest server in WTA history, recording a 130 MPH (209 km/h) serve in the first round of the Western & Southern Financial Group Women's Open qualifying tournament, held in Cincinnati, Ohio. Then, at 6 ft 2 inches and 170 lbs, she's roughly Roddick's size. 

5) Yesterday, 14-year-old Madison Keys won the first WTA match she played, averaging 101 mph on her first serve. 

Keys doesn't even have a bio on the WTA site, but I imagine she will soon since we're all so obsessed with speed.