Topic: portfolio building

this is something i have been interested in for some time .. but have found very little resources online or in person that explain a bit on building one .... so i would be interested in seeing what each of you think one should consist of and why ...

i have one in the works ... but right now it consists of over 500 photos... not something you want to cary into a potential client ... but i show it when someone wants to see some of my work ...