I've used Electronic Workbench from Multisim extensively and it's the easiest SPICE program I've used, so I recommend that. It's better as doing a virtual workbench than the others. You can drag various instruments (oscilloscope, function generator, bode plotter, etc.) to the Workbench schematic window, hook them into the schematic at the points you want to measure, and simulate from there. It also has neat options like allowing you to change certain parameters (operate a switch or change a pot value) from the keyboard and observe the results while the circuit is running.
LTspice is also good but not quite as easy to use, I think.