my 3 year old has not tried the jumpstart series yet. for now, she's happy with www.nickjr.com and www.pbskids.org. why not browse these sites? you might find other softwares there.
Just a few things my little girls (I have a 7 and 2 year old) are gaga about: Bubblegym - works with the SMS (Sudden Motion Sensor) function of the new Powerbooks and iBooks. Good for hand and eye coordination... plus the kids get good giggles off it too! Toysight - this one you can play with as long as you have an iSight. My favorite game for the kids because they don't have to touch the keyboard (even the laptop) to play it! Using the iSight as a motion sensor, the kids get to jump off a plan and freefall their way down. The pack contains a musical harp as well. Another good app for hand and eye coordination. Genius - a great freeware I got off Versiontracker. Perfect for memorizing things. Roboprog - another freeware, this time for more advanced kids. (hehehe)... its a simple programing app with a robot that jumps up and down when you complete a program task. My 7 year old loves it!