kinda depends what you need them for, but if you can afford them, got both. CiscoWorks (at least 2000, 6.0 doesn't) integrates nicely with OpenView. You could use OV to monitor the network, ports, servers, etc., and launch CW from inside OV to modify the switches and routers. Plus, it also ties in to display switch and router templates as the backgrounds to make it easier to track which port is which. Small potatoes really, but still kinda neat.
'course, you could get the Big Brother/MRTG combo for free and replace OpenView and CiscoWorks. . .
- Alex