I keep hearing that boolean operations do not yield very good results, but I’m not sure what the alternatives are and how to use them.
For the sake of creating an approachable question, let us assume that I want to make a cylindrical cup. How can I do this without placing a smaller cylinder within a larger cylinder and performing a boolean-difference?
Thank you very much,
Afsheen
Create two cylinders, same amount of vertices, cap the ends for both.
But delete one end of caps.
If you using 2.4x then you could select the open edges (CTRL-SHFT-Alt_M)
and skin the edges.
In 2.5 i don’t think they brought this back yet, so you’ll have to do it mnually, but you could also try out the solidift modifier.
The best way to make a cup is to simply extrude it. This method gives the most control over all surfaces (i.e. you can make the inside shaped differently than the outside).
See the glasses on my “Free Resources” page on my website for reference: http://robo3d.com/index.php?pr=Free_Resources_Props
But yes for a quick and dirty cup, you could, as cire792 said, use the new Solidify modifier found in Blender 2.5.
All the best 
–Robo