I'd say to just start off with a couple DC motors and a motor shield to controll them You can do most of what the other platforms offer on your own with minimal effort. You can print a fancy round frame for it if you really want one.
I like the look of the two-wheeled Turtle from DFRobot, along with their 2A dual motor controller.
The MAKE Rovera, which got one negative review, is actually a bigger, more expensive kit that appears to include the Turtle along with some other stuff, so I wouldn't let that one negative review cloud the DFRobot offering.
@Max: If you are ready to build your own robot from the ground up, let me offer my own approach.
I'm a LEGO fan since I was little child, and when I need to prototype something similar to a robot, I use to attach some bricks to the MCU boards until I get a nice Frankenstein-like thingy.
The last time I used LEGO plus electronics, I was trying to build a helicopter form factor drone: I bought a simple and big RC helicopter, a wifi enabled webcam and some LEGO Technics boxes to update my collection -- of course, the helicopter was destroyed in the first test flight ;-)
NOTE: In addition to LEGO Technics, now there are available kits for robotics such Mindstorm and NXT.
@willb6: I like the look of the two-wheeled Turtle from DFRobot, along with their 2A dual motor controller.
Thanks for the feedback, but I've sort of gone a different way -- I found an interesting base with three wheels (those strange wheels that have sub wheels on the main wheels) -- then I found a motor controller from AdaFruit that control four motors -- I'll be writing all of this up in a future blog.
As we unveil EE Times’ 2015 Silicon 60 list, journalist & Silicon 60 researcher Peter Clarke hosts a conversation on startups in the electronics industry. Panelists Dan Armbrust (investment firm Silicon Catalyst), Andrew Kau (venture capital firm Walden International), and Stan Boland (successful serial entrepreneur, former CEO of Neul, Icera) join in the live debate.