Actually, right now theInnovatek HPPS 12v Pump
(eheim mod) is really hard to beat if you have the space...and it is 12V DC, so it's quiet! A Hydor L30 is another great pump that's floating around out there. I generally didn't like the Eheim's until they got this 12V unit. They were just overpriced IMO.
If space is a concern, the little Danger Den DD12V-D4
pump is a great pump as well.
I'd look at the "rise hight" or "bars" as a good figure to compare pumps as well. If you decide to add more than CPU cooling, then pressure supply will become a large issue along with your choice of tubing diameter. And also take into account that the mixture of glycole and the likes will lower the rated performance. But basically, 160-200 GPH* is a good figure.
*Rated. As per the article below, real life rating is closer to 50.