My basic formula runs like this - when I'm negotiating, I cite my previous salary as everything I earned - salary + all bonuses plus any other perks I can cite.
When I'm comparing, I use only money I'm guaranteed: salary plus any guaranteed or performance bonuses I am confident I can hit (with targets in writing as part of my job agreement). Bonuses that are based on nomination or any other "approval" type process are really just too risky for me to consider as part of my overall compensation package. They will only factor if all else is basically equal.
When I'm comparing, I use only money I'm guaranteed: salary plus any guaranteed or performance bonuses I am confident I can hit (with targets in writing as part of my job agreement). Bonuses that are based on nomination or any other "approval" type process are really just too risky for me to consider as part of my overall compensation package. They will only factor if all else is basically equal.