I'm gonna cheat!!!
For me it's M7 because with it you get
7 for the price of 1. Within its border there also lie a globular cluster, 2 open clusters and 3 planetary nebulae.
When M7 is up I often use it to gauge the quality of seeing. If I can see the faint GC things are good.
M7 is quite an amazing cluster. It gives so much at every level of aperture, from naked eye, binos, to small & large scopes. Plenty, plenty, plenty.
Tomorrow, however, another DSO
WILL be my favourite...
