The engineering students at Rensselar Polythechnic Institute (RPI) are all required to buy & use one of these.
http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,842,1018&Prod=ANALOG-DISCOVERY&CFID=5448142&CFTOKEN=1f061da59e4fbbc4-FDF0F4AE-5056-0201-025298955CA70167
My son says it works pretty good.