Since in my urban area the creatures are used to human activity there is no need to bait as they are not as wary.
In true wild areas there is no substitute for good long glass ($$$).
I prefer not to bait, but will take advantage of natural or established feeding and nesting locations.
The bird forums will have long discussions on this subject as well as the use of recorded bird calls to attract birds.
http://www.birdforum.net/
Personally I prefer to enjoy the outdoors and if I am lucky and see a critter and happen to get a nice shot then it is an even better day.