You can go to Wikipedia (www.wikipedia.org) and view all of Calgary's neighborhoods. Easiest way to tell how "nice" they are? Look at the demographics.
Areas with higher income, obviously are "nicer." You can also tell by the "percent of homes used for renting" which is included in many neighborhoods. Areas with high rentals have little pride of ownership and it shows. You get people in and out and sometimes people setting up flop houses for druggies and hookers.
However, that's a guide, not rules set in stone. My neighborhood has a lower average income than Forest Lawn, but is considered to be a much nicer area than FL.
The "crap" neighborhoods most Calgarians avoid are Forest Lawn, Dover, and Ogden/Lynnwood. Those 3 get the worst reputation, despite other neighborhoods having issues. For example, the NE, where most immigrants seem to go, has more gang violence and gang related crime than the SE, which is where FL, Dover, and Ogden are located. Personally, I lived in FL the first 5 months I was in Calgary and had 0 problems. Never harassed, mugged, or even bothered.
For a safe bet, most areas in the NW and SW are good areas. Buuuuuuuut it all depends on your definition of "good." NE has a lot of older communities, smaller houses, and is much more diverse than the South. (By diverse, I mean racially.)
You can also review Calgary crime stats: http://crimemap.calgarypolice.ca/
If you go by car insurance rates. NE is highest. SE is lower than NE. SW is lowered than both NE and SE. (I don't know about NW.) Insurance rates are a pretty good indicator.