What does a capacitor capacity really mean?
Does a higher capacitance effect the time the charge is held?


A higher capacitance can store more charge (\$Q = CV\$), which can then supply a current for a longer period (assuming a constant load).


  If I had 5 100uf capacitors, and I connected them in parallel(which will give me 500uf), will it perform the same way as a 500uf capacitor(that was not combined with others)?


Yes.


  Does different types of capacitors hold charges longer than others?


A 1uF ceramic cap and a 1uF electrolytic cap are both 1uF, and therefore hold the same amount of charge. However, certain types of capacitors have different characteristics (ceramic caps cannot really be used to make large caps, for instance).

If you want to know how long a capacitor which is not connected to anything will hold its charge, that is dependent on the leakage current of the capacitor, which in turn is highly dependent on capacitor type and construction.