A solderless breadboard with connector breakout boards can also be used instead of a baseboard. Many surface mount ICs sensors and drivers are also available on breakout boards. A breadboard provides a bit more flexibility and it is easier to connect custom external hardware, ICs, and sensors than a baseboard. The more expensive breadboards such as the ones from 3M and Global Specialties do tend to last a bit longer under extreme use and have a sturdier base than the less expensive ones, but it is not clear if it is worth the increased price especially if it is only used occasionally.
See handbook Breadboard if you are not familiar with how to use a breadboard. An mbed module with several breakout boards requires a medium to large size breadboard. Servos and motors will need an external power source, so a breadboard with power terminals can come in handy for any projects that require more current than a USB cable can provide (460MA - 200MA needed for mbed). A new or spare AC to DC wall adapter with banana plugs that plug into the breadboard terminals can even be used as a low-cost auxiliary power supply. Low-cost small wall adapters with energy efficient switching regulators can provide up to 5V at 4A for around $20-30. Remember to connect the grounds only when using more than one power supply. The breadboard size seen below has worked well for students working on a wide variety of mbed projects.
Don't forget the jumper wires, you can never have too many. They always seem to vanish.
A 3M Jumper Wire Kit from Digikey
A low-cost Pololu Jumper Wire Refill Kit
Here are some sources for solderless breadboards: