don't waste your time with looking for the perfect comparison list, it won't help you much with making your choice. Take a more balanced approach.
First decide what you need. Is the regular Arduino good enough or do you need a version running on 3.3V, one specially small, one with motor drivers, with Blue Tooth, RTC, Ethernet, accelerometers, gyrometers, Ethernet, LED-matrix drivers or a Flash card already included or one with a lot more ports? If your answer is either "No", "I don't know" or "Maybe in the future", you don't need the speciality versions and you can go with the regular Arduino Uno or Duemilanove compatible.
Next decide on a what else you need - sensors, starter kits, booklets, displays, robot chassis, motors, Gigawatt laser turrets etc and look for a shop that sells most the stuff you want at prices you're willing to pay. Once you found that look for whatever clones they offer (and have in stock) and take the one you like most. In the end, the pricing is pretty similar and the differences are insignificant. You probably won't save mare than a dollar or two, which quickly can be eaten up by shipping when ordering elsewhere.
With this, you won't go wrong and it will save you a lot time wasted otherwise rehashing lists.