I've found that one isn't enough. To calibrate a scope, you need a scope.I will use this to see what it can do and at least get aquainted with the workings of a basic oscilloscope before making a decision about the big one!
I used my Tek466 as my "portable" scope until it broke (haven't gotten around to troubleshooting yet). Now my "go to" is an SC502 (15MHz):
If I need more channels, I use a 7704 (shown with the SC502 for scale):
The nice thing about the SC502 is I can fill the other two slots with whatever I need at the time (signal generator, power supply, frequency counter, etc).
If I want a larger screen, I use a Tek7603.